GIS and remote sensing-based site suitability analysis for a new abattoir: a case study in Adola Woyu town, Ethiopia

ABSTRACT

This study aimed to determine the ideal location for an abattoir in Adola Woyu town, taking into account environmental considerations by utilizing remote sensing and GIS, and collaborated with Ethiopia’s national urban planning agency for guidance on urban land use planning. The study analyzed various factors such as land use, cover, elevation, slope, streams, distance from roads, high-tension lines, social services, and boreholes. Researchers found acceptable areas with a highly attractive location of 1.27%, 28.42% being suitable, 21.54% being somewhat suitable, and 48.75% being unsuitable by hierarchical weighting utilizing the MCE approach. The highly desirable areas are in the north-west, north-east, and south-east, classified as bare land. The suitable areas are near the edges of built-up zones, while the unsuitable sites are in developed areas. The study’s main objective is to have the abattoir situated in an ideal location to minimize environmental impact from liquid and solid waste, airborne waste, and noise pollution while promoting sustainable land-use practices. The results are readily applicable for land-use planners and managers to make informed decisions on the strategic placement of the abattoir. By implementing the study’s recommendations, we can effectively minimize negative impacts on adjacent ecosystems while promoting responsible and sustainable development practices.

KEYWORDS:

• Abattoir
• GIS
• remote sensing
• site suitability
• MCE

1. Introduction

An abattoir, also known as a slaughterhouse, is a vital component of a modern urban community as it provides safe and hygienic conditions for the slaughter and processing of animals, enabling the production of meat products for consumption (FAO, 2021). In addition to ensuring the safety and hygiene of meat production, abattoirs also play a crucial role in regulating and inspecting the quality of meat. This helps to protect consumers from potential health risks and ensures that only high-quality meat reaches the market (World Health Organization, 2017). However, choosing the right location for an abattoir is crucial, as it could potentially impact nearby activities and pose environmental risks such as pollution and disease transmission (Marre et al., 2020). Therefore, careful consideration must be given to factors such as proximity to residential areas, transportation infrastructure, and waste management systems when selecting a suitable location for an abattoir (Ehui, 1998). Additionally, implementing strict regulations and monitoring systems can help mitigate any negative impacts and ensure that abattoirs operate in a sustainable and responsible manner (Toma et al., 2019). Site suitability analysis is critical to identifying an ideal location for the abattoir to ensure sustainability, environmental protection, and social acceptability (Gibb et al., 2018).

In recent years, the use of GIS and remote sensing technologies in site suitability analysis has become increasingly important. These technologies allow decision-makers to collect and analyze spatial data to make informed choices that minimize negative impacts on the environment and communities. GIS integrates various types of data, providing a comprehensive understanding of factors that influence location suitability. Remote sensing technologies, such as satellite imagery, aid in monitoring existing conditions and identifying potential issues. This integration in site suitability analysis revolutionizes the decision-making process, promoting sustainable development and ensuring the well-being of local communities (Nabavi et al., 2018). GIS and remote sensing data are increasingly being used in agricultural sector decision-making to identify suitable sites for industries like abattoirs. These technologies integrate geospatial datasets like satellite imagery, elevation, and transportation networks (Hamid et al., 2019). These technologies provide valuable spatial information that enables researchers and stakeholders to identify suitable sites for different agricultural industries, including abattoirs. By integrating various geospatial datasets, such as satellite imagery, elevation data, land use or land cover maps, and transportation networks, GIS helps in assessing the suitability of locations based on different criteria.

The dynamic and constantly evolving pattern of urban expansion has engendered novel challenges for urban planning and redevelopment. This growth has been linked to heightened pressure on land for human habitation and associated urban services. In view of the amplified complexity at hand, immediate attention is imperative for the future physical planning of towns and cities (Masula, 2015). One major objective of urban land use planning is to assess the merits and demerits of one land use over another. Cities and towns in the majority of developing countries undergo mounting pressure from the population on finite resources and a dearth of modern economic organization, which could ameliorate this pressure (Harris, 2013). Thus, the implications for the environment and the quality of life are of momentous significance. This is equally applicable to Ethiopia. In Ethiopia, rapid urbanization and population growth have resulted in increased demand for land and resources. As a result, effective urban land use planning becomes crucial in order to balance the needs of the growing population with environmental sustainability and improved quality of life. It is imperative for Ethiopia to prioritize comprehensive land use assessments and consider the long-term implications for both the environment and the well-being of its citizens (G/Egziabher, 2001).

Urban planning operates within a spatial context whereby considerations regarding land use and the correlation between distinct land uses take center stage (Masula, 2015). Urban planning involves the strategic allocation and organization of land for various purposes, such as residential, commercial, and recreational. It aims to create a harmonious balance between different land uses to promote efficient use of space and enhance the quality of life for residents. Additionally, urban planning also takes into account factors like transportation infrastructure, environmental sustainability, and social equity to ensure the long-term viability and success of cities. It must navigate competing objectives and balance a longing for a versatile and proficient urban milieu with the imperative mandate of resource conservation.

In preparation for rapid expansion, urban planning must furnish amenities that, though required imminently, may go to waste in the present. This calls for prescience of mind, a quality that remains challenging to achieve in a setting that is dynamic and ambiguous (Harris, 2013). Urban planning requires a forward-thinking approach that anticipates future needs and challenges. This includes considering factors such as population growth, technological advancements, and environmental sustainability. By incorporating these considerations into the planning process, cities can strive towards creating a resilient and adaptable urban environment that can thrive in the face of uncertainty. Additionally, effective urban planning should also involve community engagement and collaboration to ensure that the diverse needs and aspirations of its residents are taken into account.

Throughout history, maps have served as a means of displaying geographical data. While manual methods were once utilized, modern land suitability analysis often incorporates the process of map overlay. In his work, ‘Design with Nature’ (1969), McHarg explains how manual map overlaying can aid in systematic land use planning. GIS possesses great potential for solving environmental and human management issues, although this capability has not been fully realized (Antenucci, 1990). As ESRI (2001) puts it, the only real limit to the potential of GIS applications is the creativity of their users. Consequently, GIS is deemed an essential field of research for solving real-world issues requiring geographically-referenced data (Worboys, 1994). Regarding site selection for facilities, such as a new construction project, GIS offers the potential to explore implications for traffic, pollution, displacement of other activities, functionality of the new facility, and other relevant factors. The context and objectives of GIS technology use dictate how best to use it (Bruijn, 1990; Harris, 1990). Furthermore, for the proper use of this technology, it is essential that users, managers, and decision-makers possess a thorough comprehension of GIS (Aronoff, 1989).

The National Urban Planning Institute (NUPI) is entrusted with designing a multitude of services for urban land use development, among which include abattoirs. According to Alimentarius (1993), an abattoir is a location where animals are slaughtered and prepared for human consumption. It has received approval from the relevant authorities and is registered with them. The objective of the abattoir is twofold: to yield well-prepared meat through the use of hygienic techniques for slaughtering and dressing while, at the same time, enabling proper inspection of the meat. The demand for abattoirs has increased concomitantly with the burgeoning population and urban expansion. Nowadays, municipal abattoir facilities are included in the urban master plan and land use planning. Regrettably, in many developing countries, this facility is not well integrated into land use planning. Thus, the special siting requirements for abattoirs imposed by land use and environmental regulations need to be carefully considered. These requirements include proper waste management systems, adequate water supply, and proximity to transportation networks for efficient distribution of meat products.

Failure to integrate abattoirs into land use planning can result in negative environmental impacts such as water pollution and increased traffic congestion. Therefore, it is crucial for developing countries to prioritize the integration of abattoirs into their land use planning processes to ensure sustainable and efficient meat production. Even though the location of some urban functions, most notably slaughterhouses, poses a significant environmental risk in Ethiopia, these facilities are frequently built in inappropriate locations that endanger the surrounding areas of the population and bear the consequences of their proximity to large-scale operations (EPA; Environmental Protection Agency, 2002). This issue highlights the need for better coordination between land use planning and environmental policies to ensure the appropriate siting of abattoirs. Furthermore, a comprehensive assessment of potential environmental impacts should be conducted prior to selecting a location for an abattoir, taking into account factors such as proximity to residential areas, water sources, and waste management facilities.

However, various instances of serious problems in this matter can be observed in different towns in Ethiopia. For example, in one town, the lack of access to clean water has resulted in widespread health issues among the residents. Additionally, inadequate infrastructure and limited resources have hindered efforts to address these problems effectively. Prominently, the sites lack a significant time dimension and are quickly overwhelmed by other urban land applications, such as housing and commercial operations. Furthermore, the lack of proper waste management systems exacerbates the health issues in these towns, as waste often contaminates the limited water sources available. Moreover, the rapid population growth in these areas adds to the challenges, as it puts further strain on already limited resources and infrastructure. Consequently, the abattoirs must be relocated earlier than previously anticipated. In addition, abattoirs are sometimes situated close to waste disposal sites, exposing them to pollution. A prime illustration of this is Teppi town (G/Egziabher, 2001). The contamination of water sources by waste in these towns not only affects the availability of clean drinking water but also poses serious health risks to the local population. The combination of limited resources, strained infrastructure, and pollution from waste disposal sites near abattoirs creates a pressing need for immediate action to mitigate these issues and protect the well-being of communities. In some locations, like Durame town, abattoirs are being constructed in the central business district, reflecting a serious issue of incompatibility. In other scenarios, such as Gimbi town, abattoirs are built so near water supply dams that liquid waste disposed of joins the water, posing a severe health hazard (G/Egziabher, 2001), and various similar challenges are encountered.

Accordingly, each NUPI planning team would encounter such difficulties and must seek appropriate or optimal solutions. Several criteria are involved in locating a suitable abattoir site, all of which are critical and limit choices. The final objective of these criteria is to select a site that has minimal adverse environmental effects on the surrounding natural environment (Fard et al., 2012). An abattoir aims to produce hygienically prepared meat while also facilitating proper meat inspection. The resulting waste materials are appropriately handled to minimize potential danger or meat-borne infectious agents from reaching the public or contaminating the environment (FAO, 1992). To achieve this, the abattoir must be located in an area with proper waste management infrastructure and facilities. Additionally, it is crucial to consider the proximity of the site to residential areas or sensitive ecosystems, as well as any potential impact on water sources or air quality. By carefully evaluating these factors, a suitable site can be chosen that ensures both the production of safe meat and the protection of the surrounding environment.

A method known as the multi-criteria evaluation (MCE) technique has proven to be a useful tool in urban land use planning. This approach assists in identifying, classifying, analyzing, and organizing pertinent information relating to chosen possibilities. Its main focus is centered on effectively consolidating information from several criteria into a single index of evaluation. This methodology is utilized to address the challenges that decision-makers face in dealing with substantial amounts of intricate information. By using the MCE technique, decision-makers are able to streamline the decision-making process and prioritize options based on their overall evaluation scores. This allows for a more efficient and informed approach to urban land use planning, ultimately leading to better outcomes and more sustainable development. Additionally, the MCE technique can also help in identifying potential trade-offs and conflicts between different criteria, enabling decision-makers to make well-informed decisions that balance multiple objectives.

In the study town, the location of the abattoir site was determined through a combination of geographic information system (GIS), weighted linear combination (WLC) analysis, and remote sensing techniques. Various parameters were collected from numerous sources in vector and raster GIS formats. These parameters were then employed in a GIS-based WLC analysis to select a suitable site for the abattoir’s construction. The information gathered aided urban planners in making informed decisions regarding the selection of the best area for building an abattoir. The GIS-based WLC analysis took into consideration factors such as proximity to residential areas, transportation infrastructure, and environmental impact. Remote sensing techniques were used to assess land cover and land use patterns at the potential sites. This comprehensive approach ensured that the selected site for the abattoir would minimize negative impacts on surrounding communities and maximize efficiency in terms of transportation and waste management.

The primary aim of this research is to conduct a comprehensive multi-criteria decision analysis for the urban center known as Adola Woyu, utilizing the methods of GIS and remote sensing. Complementing the overarching objective, this study delineates the subsequent specific objectives: To evaluate the consequences of the current abattoir location on both the neighboring community and the surrounding ecosystem, to ascertain the spatial determinants influencing the choice of an alternative abattoir site for future development, and to devise a model for appraising site suitability in order to identify the most optimal location for establishing the abattoir facility. Geographic information systems and remote sensing-based multi-criteria decision-making analysis were used in this study to investigate the suitability of abattoir site selection in Adola Woyu town. The data collection for this study was undertaken in the year 2022. AHP and the weighted linear combination (WLC) technique were also applied as parts of a multi-criteria decision-making (MCDM) data analysis approach.

The primary focus of this study lies in municipal abattoirs, as they represent the predominant type in numerous towns throughout the country. The criteria for site selection were formulated primarily based on NUPI’s expertise, with the necessary adjustments being made for export abattoirs in accordance with the latest guidelines outlined by the Livestock Marketing Authority. The objective of this study is to establish an appropriate location for an abattoir within Adola Woyu town. Urban planners will be able to use this knowledge to make well-informed decisions when choosing the best locations for various urban facilities. Additionally, organizations that work to address environmental issues like noise, wastewater, and air pollution will benefit from this knowledge. Moreover, it serves as a comprehensive review of relevant literature for future studies, serving as a foundation and enriching the research findings in this field. By means of this investigation, other towns may gain valuable knowledge regarding the selection of a suitable abattoir site.

However, there is currently no systematic study available on selecting an appropriate abattoir site using remote sensing and GIS-based MCDA techniques in Adola town. This study aims to evaluate and conduct site suitability analysis in the study area for abattoir construction, incorporating remote sensing and geographic information system techniques with the integration of the MCDA approach. This methodology will provide benefits to decision-makers, stakeholders, and the town administration. By utilizing remote sensing and GIS-based MCDA techniques, decision-makers will have access to accurate and up-to-date information regarding the suitability of potential abattoir sites in Adola town. This will enable them to make informed decisions that take into consideration factors such as environmental impact, accessibility, and infrastructure availability. Ultimately, this study aims to contribute to the sustainable development of the town by ensuring the establishment of an abattoir in a location that maximizes efficiency and minimizes negative impacts.

2. Materials and methods

2.1. Description of the study area

2.1.1. Location of the study area

Adola Woyu is a captivating town located in Adola District, Guji Zone, in the Oromia region of southern Ethiopia (Figure 1). Its geographic coordinates lie between 5°48′30'' N to 5°54′12'' N latitude and 38°55′14'' E to 40°22′03'' E longitude, with an elevation that varies from 1640 to 1838 meters above sea level. This charming town is positioned 470 kilometers south of Ethiopia’s capital city, Addis Ababa. The National Meteorological Agency of Ethiopia reports that Adola Woyu town experiences a warm to hot climate during the day and cold temperatures at night, with a yearly precipitation of 1490 mm. The temperature range spans from 18°C to 24°C. The town is accessible via an asphalt road that connects Addis Ababa to Negele Town. For many years, Adola Woyu town has remained a center for commerce and trade in the region. It is worth noting that the town is divided into six kebeles, or administrative sub-cities, as indicated in the Adola Woyu town administrative report of 2023. These kebeles are responsible for the management and governance of their respective areas within the town. Each kebele has its own elected officials and is tasked with providing basic services to its residents. This decentralized administrative structure allows for efficient decision-making and a better representation of the town’s diverse population.

Figure 1. Location map of the study area.

2.1.2. Topography

The topography of Adola Woyu Town can be characterized as moderately rugged, with undulating elevations and disjointed micro-relief. The terrain itself is relatively level, though it ranges in altitude from 1640 to 1838 meters above sea level and exhibits slopes ranging from 2 to 47 degrees. As per the agricultural office report for the 2023 Adola district, the land in this region may be classified into three distinct categories: highland (15%), midland (55%), and lowland (35%). These classifications are based on the altitude and slope of the land, with highland areas having steeper slopes and higher elevations, midland areas being relatively flat with moderate slopes, and lowland areas being the flattest with the lowest elevations. These variations in topography contribute to the diverse agricultural practices and land use patterns observed in Adola Woyu town.

2.1.3. Elevation

The height of a location above or below a reference level, such as the mean sea level, is referred to as elevation. Elevation is an important factor in determining the climate, vegetation, and accessibility of a location. It can also impact the availability of natural resources and their suitability for human habitation. The position, angle, and stage must all be taken into account while assessing the terrain and its components for the establishment of an appropriate abattoir site. The digital elevation model (DEM) was used to generate the elevation factor (Figure 2). The DEM provides a detailed representation of the elevation of the terrain, allowing for accurate analysis and decision-making in site selection. By incorporating elevation data into the assessment process, potential challenges such as steep slopes or low-lying areas prone to flooding can be identified, ensuring the chosen abattoir site is suitable and sustainable in the long term. The research area’s elevation varies from 1640 m at its lowest point to 1838 m at its highest. The suitability of the landscape for allocating urban land use was used to evaluate the elevation classes. The elevation classes were categorized based on their suitability for urban land use, with higher elevations being less suitable due to factors such as steep slopes and limited accessibility. This evaluation helped in determining the most appropriate location for the abattoir site, considering both the terrain characteristics and the surrounding urban development plans.

Figure 2. Elevation map.

2.1.4. Slope

Slope is a crucial factor to consider when looking for suitable locations for urban development in hilly terrain. The slope of the land affects various aspects of urban development, such as construction costs, drainage systems, and accessibility. Steeper slopes may require more extensive and expensive engineering solutions to ensure stability and prevent erosion. Additionally, the slope can impact the efficiency of transportation networks and the feasibility of building infrastructure like roads and buildings. Steep slopes are disadvantageous for construction because they increase construction costs, limit maximum floor areas, and contribute to erosion during construction and subsequent use. Moreover, steep slopes can also pose challenges for the installation of utilities such as water and sewer lines, as well as for the implementation of landscaping and vegetation. These factors further add to the complexity and cost of construction projects on steep slopes. The general physical characteristics of the study area are depicted on thematic maps in Figure 3. The area’s slope ranges from 2 (gentle slope) to 47.75 (very steep slope) degrees, as seen on the map. A slope map was generated through the interpretation of the DEM that covers the study area. The slope map provides valuable information about the topography of the study area, allowing for a better understanding of the challenges that construction projects on steep slopes may face. It also helps in identifying areas that require special attention and mitigation measures to ensure safe and stable development. Additionally, the slope map can be used as a tool for effective land-use planning and decision-making, guiding the selection of suitable locations for different types of development activities.

Figure 3. Slope map.

2.1.5. Demographics

According to the 2007 national census, this town had a total population of 22,938, of whom 11,706 were men and 11,232 were women. Because of demographic uncertainties, such as high net migration and natural population increments, the exact number of inhabitants is not known. But, according to the national census, the total population projected for 2021 of the town is 47,573, of whom 24,037 were male and 23,536 were women. The town’s population growth can be attributed to factors such as increased job opportunities and improved infrastructure, which have attracted migrants from surrounding areas. Additionally, the town’s healthcare facilities and educational institutions have contributed to a higher birth rate, further adding to the population increment. Furthermore, the town’s favorable living conditions and quality of life have also played a role in attracting individuals and families to settle down in the area. As a result, population growth is expected to continue in the coming years as the town continues to develop and offer opportunities for both residents and newcomers.

2.1.6. Land use

Based on the remote sensing image, the land use and cover map of the study area was classified into seven categories: built-up area, agricultural land, barren land, forest land, stream, vegetation, and wetland (Figure 4). Accordingly, areas occupied by wetland and streams are insignificant, whereas built-up areas, agricultural lands, and vegetation cover a larger area. The other dominant land use or cover type is forest. The classification was done on a Sentinel 2A 2023 image at 10 m resolution downloaded from the Copernicus Open Access Hub (https://scihub.copernicus.eu/). The classification of land use and cover categories was performed using a supervised classification algorithm, taking into account spectral signatures and texture analysis. The Sentinel 2A image provided high-quality data for accurate classification, enabling the identification and mapping of different land use types within the study area. The land use map provides valuable information for understanding the distribution and extent of different land cover types within the study area. This information can be used to assess the impact of human activities on the environment, identify areas of conservation importance, and plan for sustainable land management practices. Additionally, monitoring changes in land use and cover over time can help detect trends and patterns that may have implications for ecosystem health and biodiversity. Furthermore, the land use map can support decision-making processes related to urban planning, resource allocation, and disaster management. It can also aid in identifying areas prone to deforestation or degradation, allowing for targeted interventions and mitigation strategies. Overall, the land use map serves as a crucial tool for promoting sustainable development and ensuring the preservation of natural resources.

Figure 4. Land use map.

2.2. Research methodology

2.2.1. Data acquisition

Table 1 illustrates the various data categories covered in the study as well as their sources of origin. It also shows the collection of both spatial and non-spatial data from primary and secondary sources.

Table 1. Sources of data used in the study.

Data	Data source	Purpose
Sentinel-2A 2023, 10m resolution	Copernicus Open Access Hub (https://scihubcopernicus.eu/)	LULC classification
SRTM DEM (30m)	https://www.usgs.gov/	To derive slope and elevation
Structural Plan of the Town	Municipality	For digitization of roads and high-tension lines
Boundary map	The structural plan of the town	To delineate the study area
GPS data	Field survey	To identify parameters (existing abattoir, social service, and borehole)
Meteorological data	Regional Meteorological Service	To identify weather conditions

2.2.1.1. Primary data sources

Spatial data is collected by using a GPS instrument in the field. It includes information about the location and shapes of geographical features and the relationship between them. This data is crucial for various applications such as mapping, urban planning, environmental monitoring, and navigation systems. Additionally, spatial data can also provide valuable insights for analyzing patterns, trends, and relationships between different geographic phenomena. For instance, the spatial data are shape files created on the arc catalog and exported to the arc map, such as roads, social services, boreholes, and boundaries. These shape files can be used to analyze and visualize various aspects of the geographical features. Spatial data also includes attributes such as population density, elevation, and land use, which provide additional information for analysis and decision-making processes.

Non-spatial data is tabular or textual data describing the geographic characteristics of features. And also, non-spatial data is the data collected orally and discussed with urban planning experts who are involved in the preparation of the development plan for Adola Woyu town. Direct and indirect, unstructured interviews were conducted with the experts during the field survey to gather more information. The information derived from this study was used to identify and develop priority criteria and factors for the selection of an abattoir site. It was also used to identify problems in the study area and prioritize the potential abattoir sites in the study town. Additionally, the experts provided valuable insights on the current infrastructure and land use patterns in Adola Woyu town. This information was crucial in determining the feasibility of establishing an abattoir and ensuring its compatibility with the existing urban fabric. Furthermore, the interviews shed light on the social and environmental impacts that should be considered when selecting an abattoir site, helping to create a more comprehensive decision-making process.

2.2.1.2. Secondary data sources

The secondary data is mainly obtained from published or unpublished books, laws and regulations, a strategic plan, and satellite images of the study area. A variety of data was collected from different types of sources. The town’s Department of Urban Planning contributed the secondary data, which included boundary maps, a structural plan, land use and cover information from the Sentinel 2A 2023 image at 10 m resolution, and census-based demographic information. In addition, the secondary data also included reports and studies conducted by other research institutions and organizations that focused on similar topics or issues related to urban planning and development. These sources provided valuable insights and analyses that complemented the primary data collected for the study. The online searches were particularly helpful in obtaining satellite imagery and digital elevation models (DEM) from the US Geological Survey’s Landsat program. These data sources provided important visual and spatial information that enhanced the analysis of urban planning and development patterns. Additionally, the literature review helped to establish a theoretical framework for the study and provided a broader context for understanding the findings.

2.2.2. Software used in the analysis

The thematic maps were prepared, edited, overlaid, and visualized on the basis of the site suitability analysis for the abattoir using ArcMap 10.8 software from ESRI. The application of GIS for overlaying thematic layers to establish land databases requires that all the layer maps be converted into a common coordinate system. ArcMap 10.8’s advanced spatial analyst extension was used for reclassification, proximity analysis, and producing maps and graphics. It was also used for statistical manipulation and report generation. Additionally, the spatial analyst extension in ArcMap 10.8 allowed for the calculation of distance and proximity measurements, aiding in the identification of suitable locations for the abattoir. The generated maps and graphics provided a clear visualization of the site suitability analysis, facilitating informed decision-making processes for stakeholders involved in the project. QGIS was used to classify the land use and cover map of the study area. QGIS provided a comprehensive set of tools for land use classification, allowing for the identification and categorization of different land cover types in the study area. This information was crucial in understanding the existing landscape and its potential impact on the abattoir’s operations. Furthermore, QGIS’s ability to integrate with other data sources enhanced the accuracy and reliability of the land use classification results. Other software used in this research includes Microsoft Word, Excel, and PowerPoint. These software programs were utilized for data organization, analysis, and presentation purposes. Microsoft Word was used for writing and formatting the research report, while Excel was employed for data manipulation and statistical calculations. PowerPoint aided in creating visually appealing presentations to effectively communicate the findings of the study.

2.2.3. Instruments used for data collection

During field work, a Global Positioning System (GPS) receiver, digital camera, and compass were used to collect field data. The GPS receiver was utilized to accurately record the coordinates of each data point, ensuring precise geolocation information. The digital camera was employed to visually document the field site, capturing images that could later be referenced for further analysis or verification purposes. The compass was also essential in determining the direction and orientation of the field site, aiding in mapping and navigation. Additionally, the GPS receiver allowed for easy integration of the collected data with existing geographic information systems for comprehensive analysis and visualization. Overall, the combination of these tools provided a robust and efficient method for gathering accurate geospatial data in the field. The integration of geolocation information with visual documentation, compass readings, and GPS data enhanced the accuracy and reliability of the collected data, making it easier to analyze and interpret for research or planning purposes.

2.2.4. Data analysis method

2.2.4.1. Research geo-database design

In addition to urban land use, the geo-database also comprised data about the land cover, elevation, slope, road, streams, high-tension lines, social services, existing abattoirs, and boreholes in order to maintain the obtained data and the analytical results in a logical arrangement. The factors in play were examined with regard to their relative significance in order to pinpoint areas of high appropriateness and apply weights. This analysis helped prioritize the different land use categories based on their importance and impact on the city’s development. Additionally, the evaluation of these elements allowed for a comprehensive understanding of how they interacted with each other and influenced urban planning decisions. Additionally, the classes within each reclassification element were contrasted with one another and ordered according to how much they contributed to the final product. Through a supervised classification method using sentinel photos, data on land use and land cover were gathered. Automation (digitalization and clipping of the data by the study area border) was used to digitize the acquired data and organize it into logical factor groupings. The results of the supervised classification method provided valuable insights into the spatial distribution of different land use and land cover categories within the study area. This information can be further utilized to understand patterns and trends, enabling effective land management and planning strategies. According to the nature of the factor layers, they were divided into five groups:

• Urban land use factors: built-up area, stream, forest, agricultural land, bare lands, wetland, and vegetation land.

• Topographical: elevation, slope

• Accessibility: distance from major roads

• Surface water: streams.

• Constraints: location in terms of distance, high tension lines, social services, and boreholes.

On the basis of the remote sensing image, the land use and cover map of the study area was divided into seven categories, including populated areas, agricultural land, desert land, forest land, streams, vegetation, and wetland areas. Therefore, the areas of wetlands and streams are insignificant, whereas cultivated land and developed vegetation cover a larger area. The classification for the current research year is done using the Sentinel-2A image. The Sentinel-2A image provides a more detailed and accurate classification of the land use and cover map compared to previous methods. This allows for a more precise analysis of the distribution and changes in built-up areas, agricultural land, barren land, forest land, and vegetation over time.

The supervised classification method was used to categorize the land use and cover of the research area. The accuracy evaluations were completed in order to compare the categorized data to actual ground-truth geographic data.

2.2.4.2. Spatial multi-criteria decision making

A set of mathematical tools and methods known as multi-criteria analysis allows for the comparison of various alternatives based on a number of different, frequently competing criteria in order to direct the decision-maker towards a wise choice. Multi-criteria analysis takes into account the importance and weight of each criterion, enabling decision-makers to make informed and rational decisions. By considering multiple factors simultaneously, it provides a comprehensive evaluation that helps in identifying the most suitable alternative. The major goal of this study is to find an appropriate location for an abattoir using a multi-criteria decision-making (MCDM) strategy combined with a geographic information system and remote sensing methods. Spatial Multi-Criteria Decision Making (MCDM) is a process that combines and transforms geographical data into a decision. MCDM, combined with GIS data, is a powerful approach to systematically and comprehensively analyzing a problem. By integrating MCDM with GIS data, decision-makers can consider various factors, such as land use, proximity to residential areas, transportation infrastructure, and environmental impact, when determining the optimal location for an abattoir. This approach allows for a more informed and objective decision-making process, minimizing potential conflicts and maximizing the overall efficiency and sustainability of the chosen location. The fundamental components of a multi-criteria problem are human value judgment and assessments of the importance of criteria. The main purpose of multi-criteria evaluation techniques is to investigate a number of alternatives in light of multiple criteria and conflicting objectives. By using multi-criteria evaluation techniques, decision-makers can consider various factors, such as environmental impact, economic viability, and social implications, when selecting the most suitable location for an abattoir. These techniques help in identifying the trade-offs and synergies between different criteria, enabling a comprehensive analysis of the alternatives available. Ultimately, this approach ensures that the chosen location aligns with the overall goals and priorities of all stakeholders involved.

2.2.4.3. Analytic hierarchy process (AHP)

The Analytic Hierarchy Process (AHP), first introduced by Saaty (1980), is a widely used method in MCDM. It is easily implemented as one of the MCDM techniques. AHP is a decision-support tool that can be used to solve complex decision problems. It uses a multilevel hierarchical structure of objectives, criteria, sub-criteria, and alternatives. AHP uses a fundamental scale of absolute numbers to express individual preferences or judgments. This scale allows decision-makers to quantify their preferences and compare the relative importance of different criteria and alternatives. AHP also incorporates a pairwise comparison process, where decision-makers compare each criterion or alternative to every other criterion or alternative to determine their relative importance. This systematic approach helps to ensure consistency and transparency in the decision-making process.

AHP is categorized under the multi-criteria decision analysis approach and is an effective technique that helps planners and decision-makers analyze all data before arriving at a final decision for future land-use changes (Hieu et al., 2006). AHP has been integrated with GIS tools to identify the importance of the criteria used and to calculate weights by using a scale of importance and the opinion of experts (Mohammed et al., 2013). This integration allows for a more comprehensive and objective evaluation of different land-use options, taking into account various factors such as environmental impact, social implications, and economic feasibility. By incorporating both quantitative data and expert opinions, AHP-GIS can provide valuable insights for informed decision-making in land-use planning.

In general, nine objects are the most that an individual can simultaneously compare and consistently rank. The score of differential scoring assumes that the row criterion is of equal or greater importance than the column criterion. This means that when using differential scoring, the individual assigns scores to each object based on how well they meet the row criterion compared to the column criterion. The differential scoring method allows for a more nuanced and precise ranking of objects based on their performance in relation to specific criteria.

Table 2 shows the reciprocal values (1/3, 1/5, 1/7, 1/9) that have been used where the row criterion is less important than the column criterion. To ensure the credibility of the relative significance used, AHP also provides measures to determine the inconsistency of judgments mathematically. Based on the properties of reciprocal matrices, the consistency ratio (CR) will be calculated. The consistency ratio helps to assess the reliability of the judgments made in the AHP method. If the CR is within an acceptable range, it indicates that the judgments are consistent and reliable. However, if the CR exceeds a certain threshold, it suggests that there may be inconsistencies in the judgments, and further analysis may be required.

Table 2. The preference scale for pair-wise comparison in AHP.

Intensity of importance	Definition
1	Equal importance: Two activities contribute equally to the objective.
3	Moderate importance: Experience and judgment slightly favor one activity over another.
5	Essential or strong importance: Experience and judgments strongly favor one activity over another.
7	Very strong or demonstrated importance: An activity is strongly favored, and its dominance is demonstrated in practice.
9	Extreme importance: The evidence favoring one activity over another is of the highest possible order of affirmation.
2,4,6,8	Intermediate values between the two adjacent judgments are needed when the above numbers compromise.
1/2,1/3,1/4,1/5,1/6,1/7, 1/8,1/9	Reciprocal values of the previous appreciation.

2.2.4.4. Weighted linear combination

The weighted linear combination (WLC) approach is the most commonly used GIS-based decision-rule technique (Hopkins, 1977). It involves assigning weights to different criteria based on their relative importance and then summing the weighted scores to make a decision. This approach allows for a systematic and quantitative analysis of spatial data, making it a valuable tool in various fields such as urban planning, environmental management, and site selection. The decision maker determines and assigns the weights of relative importance directly to each attribute map layer. The total score for each alternative is the product of the importance weight assigned to each attribute multiplied by the scaled value given for that attribute to the alternative, and then summing the products over all attributes. The scores are calculated for all of the alternatives. The one chosen is the one with the highest overall score. This method of decision-making, known as the weighted sum model, allows for a systematic and objective evaluation of alternatives based on their attributes. By assigning importance weights and considering the scaled values of each attribute, the decision-maker can prioritize and select the alternative that best aligns with their goals and objectives. Additionally, this approach provides a quantitative measure to compare and rank alternatives, facilitating a more informed decision-making process.

The method can be executed using any GIS system with overlay capabilities. The use of the method allows the evaluation criteria map layers to be combined in order to determine the resulting composite map layer. Both raster and vector GIS environments can be used to implement this technique. With the weighted linear combination, factors are combined by first applying a weight to each factor, followed by a summation of the results to yield a suitability map:

$S=\sum wixi$

Where S is suitability, wi is weight of factor, and xi is the criterion score of factors. This method is highly popular, mainly due to the ease associated with its implementation within the GIS environment using map algebra operations and cartographic modeling (Tomlin, 1990). The method is intuitive, simple to comprehend, and thus appealing to decision-makers (Figure 5).

Figure 5. General work flow of the study.

3. Results and discussions

3.1. Consequences of the current abattoir

The site selected for the existing abattoir was not scientifically selected in the town (Figures 6 and 7); as a result, the existing site is nearest to a solid waste disposal site and to a built-up area and stream. The traditional practice of abattoirs has had a devastating effect on the environment, public health, and residents in particular. Abattoirs, in their traditional form, often lack proper waste management systems, leading to the contamination of nearby water bodies and soil. This not only poses a threat to public health but also disrupts the ecological balance of the surrounding area. Additionally, the proximity of the existing abattoir to a built-up area increases the risk of noise pollution and unpleasant odors for residents living nearby.

Figure 6. Existing abattoir surround.

Figure 7. Existing abattoir inside the fence.

The current abattoir in Adola Woyu town has been providing slaughtering services for a long time. It has become a vital hub for the local community, ensuring a steady supply of fresh meat. However, due to increasing demand and advancements in technology, there is a need to modernize the abattoir to meet higher standards of hygiene and efficiency. More people now live in the town than was initially anticipated, and more cattle are being butchered every day. The outdated infrastructure of the current abattoir is unable to handle the growing demand, leading to potential health and safety risks. Additionally, modernizing the abattoir would not only improve the quality of meat but also create employment opportunities for the local community, contributing to economic growth in Adola Woyu town. According to this viewpoint, the current abattoir does not satiate user interests as a result of the increase in population and the growth of the town. As per my observations and the information I have obtained from experts, The location of the current abattoir is likely to be inconvenient due to the current residential area growth, proximity to a stream (on which typically urban low-wage classes depend) for domestic usage, and other urban amenities like commercial hubs. Waste is not being managed properly. As shown in Figures 6 and 7, solid waste is discarded as refuse inside and outside the fence. This improper waste management can lead to environmental pollution and health hazards for the residents. It is crucial to relocate the abattoir to a more suitable location that is away from residential areas and has proper waste disposal systems in place.

Additionally, the area around the abattoir is more likely to contain stray bones and hairs, and liquid wastes from the abattoir that contained blood and organs with infections like the liver and kidneys were dumped directly into a stream not far away (Figures 8 and 9). The abattoir typically doesn’t handle, process, or separate the solid and liquid wastes it produces in a proper manner. As a result, they are polluting the area, particularly the neighboring stream, which has an impact on the health of those who live downstream. The abattoir’s location must not be in a place where there is a chance of flooding, landslides, or building damage (LMA, 2000). There is a possibility of flooding because the current abattoir site is situated in a wetland land classification. The road in the vicinity of the abattoir must be kept clean and in good working order (WHO, 1984). Separate entrances and exits for live animals and carcasses are required, but not for abattoirs that already exist. According to observation, the current slaughterhouse is situated in a risky area that could be contaminated with dangerous elements from the surrounding agriculture and streams. The waste from current abattoirs may pose a serious threat to human health. Solid waste in the vicinity of the abattoir is directly or indirectly harming the ecology. The presence of solid waste near the abattoir not only poses a threat to the environment but also has the potential to contaminate nearby water sources, further endangering both human and animal health. It is crucial to implement proper waste management systems and establish a new slaughterhouse in a safer location to mitigate these risks and ensure the well-being of both the community and the ecosystem.

Figure 8. Solid waste disposal around the existing abattoir.

Figure 9. Waste from the existing abattoir in town.

3.2. Criteria for map generation and classification for abattoir site selection

As a spatial decision-making process, site suitability analysis involves several steps or procedures. Among other things, identifying site selection criteria is a critical step. These criteria can vary depending on the specific project or objective, but they generally include factors such as accessibility, land use compatibility, environmental impact, and infrastructure availability. Once the criteria are established, data collection and analysis are conducted to evaluate potential sites based on these factors. Table 3 shows the criteria for the suitability of the abattoir location (LMA, 2000). The criteria serve as a framework for a better understanding of the various specific objectives and spatial entities involved in the overall suitable site designation process for the abattoir. As can be noted, the overall objective is to designate a suitable site for an abattoir. This involves considering factors such as proximity to livestock sources, access to transportation routes, the availability of utilities, and compliance with environmental regulations. Additionally, the criteria may also take into account the potential impact on surrounding communities and the overall economic viability of the chosen location. To fulfill this objective, the following site selection criteria are considered (Table 3).

Table 3. The criteria for the suitability of the abattoir location.

SN	Spatial Data	Layer Name	Criteria
1	Boreholes	Borehole	300 meters away from the borehole
2	Waste Dump Site	Waste Dump	500 meters away from the waste dump
3	Rivers and streams	River/Streams	100 meters away from the river or stream
4	High-Tension Line	High/Tension Line	500 meters away from the High/Tension Line
5	Bare land/agriculture	Bare land/agriculture	Select bare land or agricultural land.
6	Slope	slope	Between 2–10%
7	Road Network(streets)	Road	Between 20 and 400 meters from the existing road
8	Site Capacity	Site capacity	Greater than or equal to one hectare
9	Boundary/Town Area	Boundary	within the municipal boundary
10	Social services	Social services	300 meters away from social services
11	Elevation	Elevation	Lower level of the city

3.3. Classification of criteria maps

The criteria discussed above can be summarized as constraints and factors. Constraints are those criteria that constrain or limit the areas for abattoir sites. Factors, on the other hand, are the elements that influence the selection of abattoir sites but do not necessarily restrict them. These factors can include proximity to transportation routes, availability of utilities, and compatibility with surrounding land uses. In this case, the constraints differentiate between areas or alternatives that one can consider suitable for an abattoir site and alternatives that are not suitable. Factors, however, are criteria that define some degree of suitability for all geographic regions. They define areas or alternatives in terms of a continuous measure of suitability and, in fact, enhance or detract from the alternatives under consideration outside the areas that have been constrained. Thus, all criteria and constraints in the form of GIS-based layers were incorporated for site suitability evaluation for the abattoir. The incorporation of GIS-based layers allows for a comprehensive evaluation of site suitability for the abattoir. By considering various criteria and constraints, such as environmental impact, proximity to transportation routes, and availability of resources, a more informed decision can be made regarding the selection of an appropriate location. Additionally, this approach ensures that alternatives that do not meet the necessary criteria are excluded from consideration, streamlining the decision-making process. Please note that these factor maps were overlaid together for the final suitability classification of the study area. However, in this process, the data for all the selected factors is kept, displayed, and managed individually. It is impossible to compare the factors based solely on their raw scores because they are measured on various scales. Therefore, in order to allow comparability, the factor maps were standardized. Standardization allows comparison of criterion scores within one alternative. In order to standardize, the raster features of all the factors were reclassified into a common scale range. This common scale range ensures that the values of all the factors are consistent and comparable. Standardization also helps in identifying the relative importance or contribution of each factor to the overall analysis. By reclassifying the raster features into a common scale range, it becomes easier to analyze and interpret the data, facilitating more accurate decision-making processes.

3.3.1. Urban land use

The land use of the study area was produced using Sentinel-2, acquired in 2023. Classified pixels were clustered into the following seven general categories: built-up lands, agricultural lands, forest lands, stream land, bareland, wetland, and vegetation land (Figure 10). The classification of urban land use and cover involves the evaluation and grouping of specific areas of land in terms of their suitability for a defined use. Then each of the land use and cover types was reclassified into four classes based on their importance to evaluate a suitable site to locate an abattoir for overlay analysis. These are built-up areas, barren lands, agricultural land, and vegetation (Fard et al., 2012). The classification of urban land use and cover is essential for urban planning and development. It helps in identifying the most suitable areas for different purposes, such as residential, commercial, or industrial use. By reclassifying the land use and cover types into specific classes, it becomes easier to evaluate the potential sites for specific purposes, like locating an abattoir. This overlay analysis allows for a more informed decision-making process regarding the selection of a suitable site that takes into account various factors, such as accessibility and environmental impact. According to national urban planning institute experience, bare lands and agricultural lands are more preferable for the location of abattoirs. This is mainly due to the low cost of acquisitions. Thus, barren lands are ranked as most suitable; forest lands are ranked as moderately suitable; vegetation and agricultural land are ranked as suitable; built-up lands and both wetland and stream are unsuitable (Figure 11). The ability to minimize environmental impact is another factor that influences the choice of agricultural and bare lands as the location of abattoirs. These areas often have fewer ecological sensitivities compared to forest lands or wetlands, making them more suitable options for the establishment of abattoirs. Additionally, the low cost of acquiring barren or agricultural lands further contributes to their ranking as the most preferable locations for abattoirs, according to the experience of the national urban planning institute.

Figure 10. Major land use types classified from the sentinel-2A image.

Figure 11. The reclassified land use map of the study area.

3.3.2. Accuracy assessment

The method of accuracy assessment used a confusion or error matrix. Information concerning actual and anticipated classifications made by a classification system can be found in a confusion matrix. The image pixel that was classified was compared to the same location in the field. Users often receive both the overall accuracy of the map and the accuracy for each class on the map as a result of an accuracy assessment. This accuracy assessment was made for the land use and land cover of the study area (Table 4). The confusion matrix provides valuable insights into the performance of the classification system by displaying the number of correctly and incorrectly classified pixels for each class. It allows users to identify any patterns of misclassification and assess the reliability of the classification results. Additionally, the accuracy assessment in Table 4 offers a comprehensive evaluation of the land use and land cover classification in the study area, providing a detailed understanding of the map’s overall accuracy and class-specific accuracies.

Table 4. Error matrix showing classification accuracy of the true land cover.

	Built-up	Forest land	Agriculture land	Wetland	Stream	Vegetation land	Barren land	Total User’s
Built-up	45	-	1	-	-	3	1	50
Forest land	-	45	1	1	-	-	-	47
Agriculture land	1	4	42	-	-	3	-	50
Wetland	-	6	6	36	-	-	-	48
Stream	-	1	5	1	45	-	-	52
Vegetation land	-	3	4	-	-	43	-	50
Barren land	-	7	-	-	-	4	41	52
Total Producer’s	46	66	59	38	45	53	42	349

Besides the overall accuracy, the classification accuracy of individual classes was calculated in a similar manner. The two approaches are the user’s accuracy and the producer’s accuracy. The producer’s accuracy is derived by dividing the number of correct pixels in one class by the total number of pixels as derived from reference data.

In this study, the producer’s accuracy measures how well a certain area has been classified. It includes the error of omission, which refers to the proportion of observed features on the ground that are not classified in the map. Meanwhile, the user’s accuracy is computed by dividing the number of correctly classified pixels in each category by the total number of pixels that were classified in that category (Table 4). The producer’s accuracy is an important metric as it indicates the reliability of the classification results. It helps in assessing the overall accuracy of the map by taking into account the features that were missed during classification. On the other hand, the user’s accuracy provides insights into how well each category has been classified, allowing for a more detailed evaluation of the classification performance.

3.3.3. Overall accuracy

It is computed by dividing the total number of correctly classified pixels by the total number of reference pixels. It shows the overall result of the tabular error matrix. To compute the overall accuracy assessment, they used 349 reference points. Then, the overall accuracy performed in the study was 85.1% (Table 5). The minimum overall accuracy value computed from an error matrix should be 85%, according to Anderson (1976), for a reliable land cover classification. Therefore, the overall accuracy of the study land use/cover map was above 85% based on Anderson’s criteria. The 2022 supervised classification with an overall accuracy of 85.1% was achieved with a Kappa coefficient (K) of 0.851. The percentage that represents classification accuracy is typically calculated by multiplying this quantity, which stands for agreement, by 100. Therefore, the K value of 0.851 represents a probable 85.1% better accuracy than if the classification resulted from a random assignment.

Table 5. Users and producers’ accuracy.

Classified data	User’s accuracy (%)	Producer’s Accuracy (%)
Built-up	90	97.8
Forest land	95.74	68.17
Agriculture land	84	87.6
Wetland	75	94.7
Stream	86.5	100
Vegetation land	86	81.1
Barren land	78.85	97.6
Overall Accuracy		85.1%
Kappa		0.851

According to national urban planning institute experience, the bare land classification is more preferable than others for the location of abattoirs (Table 6 and Figure 11). This preference is based on several factors, such as accessibility, environmental impact, and future expansion possibilities. The classification of bare land ensures that abattoirs are located in areas that are easily accessible for the transportation of livestock and the distribution of meat products. Additionally, the use of bare land minimizes the potential negative environmental effects that may arise from locating abattoirs in already-developed or residential areas. Furthermore, the classification of bare land allows for future expansion of abattoirs if needed, as there is ample space available for infrastructure development. This ensures that the abattoirs can adapt to increasing demands in the meat industry without causing disruptions or encroaching on existing urban areas.

Table 6. Reclassified land use.

Urban land use type	Value	Level of Suitability
Built-up, stream, and wetland	1	Unsuitable
Forest	2	Moderately suitable
Agricultural and vegetation land	3	Suitable
Bare land	4	Highly suitable

3.3.4. Topographical factor

Topography is an essential aspect of understanding the Earth’s physical characteristics and its relationship with human activities. It plays a crucial role in shaping the distribution of rivers, mountains, valleys, and other natural features, which in turn influence the availability of resources and suitability for human settlement. Additionally, topography also influences weather patterns and climate variations by affecting wind flow and precipitation distribution across different regions. Topography describes the surface shape and relief of the land. It refers to various landforms (physical features) that represent the external shape of the earth. It determines the patterns and forms of many other landforms and landcover features. For example, mountains and valleys can create barriers that affect the movement of air masses, leading to variations in temperature and rainfall. Additionally, topography plays a crucial role in determining the distribution of natural resources such as water bodies, minerals, and fertile soil. These factors greatly impact the suitability of an area for human settlement and economic activities. Furthermore, elevation and slope should be considered when selecting a site for the abattoir construction project. The elevation and slope of the chosen site for the abattoir construction project can affect factors such as drainage and accessibility. Steep slopes may require additional engineering measures to ensure proper water management and transportation of goods. Additionally, higher elevations can also impact the availability of resources such as water and electricity, which are essential for the operation of an abattoir.

3.3.5. Elevation

In this study, an elevation factor was generated from the digital elevation model (DEM) using the ArcGIS spatial analyst extension of the surface module, which enabled us to classify the area according to the level of elevation. Then, the elevation raster was reclassified into four classes by examining the value and frequency of elevation in the study area (Figure 12). The four classes were defined as unsuitable, moderately suitable, suitable, and highly suitable. This classification allowed for a more detailed analysis of the topographical characteristics of the study area. Additionally, the reclassification provided valuable information for further investigations on the relationship between elevation and other variables such as land cover or precipitation patterns. By categorizing the elevation into distinct classes, researchers were able to gain a comprehensive understanding of the topographical variations within the study area. This classification not only facilitated a more nuanced analysis of the terrain but also paved the way for exploring how elevation interacts with other environmental factors in shaping the region’s characteristics. Furthermore, this reclassification serves as a valuable foundation for future studies investigating the complex interplay between elevation, land cover, and precipitation patterns in the study area.

Figure 12. Reclassified elevation map generated from DEM.

According to Fard et al. (2012), abattoirs might be constructed in an area lower than the city level in order to prevent the spread of contamination. Therefore, areas with high altitude were ranked as unsuitable, and areas with low altitude were ranked as highly suitable for site selection (Table 7). The study also highlighted the importance of selecting sites that are away from residential areas to minimize any potential negative impact on the local community. Additionally, factors such as proximity to transportation routes and the availability of utilities were taken into consideration during the site selection process.

Table 7. Reclassified elevation values.

Elevation(m)	Value	Level of Suitability
1760–1838	1	Unsuitable
1720–1760	2	Moderately suitable
1680–1720	3	Suitable
1640–1680	4	Highly suitable

3.3.6. Slope

Slope is an important criterion in hilly terrain for finding suitable sites for urban development. Steep slopes are disadvantageous for construction. Steeper slopes increase construction costs, limit maximum floor areas, and contribute to erosion during construction and subsequent use. In this study, a slope factor was created from the digital elevation model (DEM) using the ArcGIS spatial analyst extension of the surface module, allowing us to categorize the area based on how steep and flat the terrain is. The slope function could calculate the maximum rate of change between each cell and its neighbors. Every cell in the output raster had a slope value. The lower the slope value, the flatter the terrain was, and the higher the slope value, the steeper the terrain. Then the slope raster was reclassified into four classes of slope percent by examining the value and frequency of slope percent in the study area (Table 8 and Figure 13). The reclassified slope was given a rank value of 1 to 4, with the higher value of 1 showing unsuitable and the lower value of 4 showing highly suitable. Thus, according to LMA (2000), a gently sloping area between 2 and 10 percent is suggested as the ideal slope for an abattoir site. Slope values below 2 percent are not suitable from a safe drainage point of view. This classification of slope percent allows for a clear understanding of the suitability of different areas for the abattoir site. Areas with a slope percentage greater than 10 are deemed unsuitable due to safety concerns related to drainage. Additionally, areas with a slope percent between 2 and 10 are considered highly suitable as they meet the recommended criteria for a gently sloping area. These areas provide optimal conditions for effective drainage and minimize the risk of flooding or water accumulation around the abattoir site. It is important to prioritize these highly suitable areas when selecting a location for the abattoir to ensure the proper functionality and safety of the facility.

Figure 13. Reclassified slope map generated.

Table 8. The reclassified slope suitability class.

Slope (%)	Value	Level of Suitability
<30	1	Unsuitable
21–30	2	Moderately suitable
11–20	3	Suitable
2–10	4	Highly suitable

3.3.7. Accessibility

3.3.7.1. Roads

Roads are also an important criterion in site suitability analysis. The need to transport processed meat and slaughtered animals is dependent on their proximity to transportation facilities. Therefore, efforts were made to locate the site nearer to any existing road if possible. In addition, the availability of a well-connected road network can greatly impact the efficiency and cost-effectiveness of transportation. This is particularly crucial for ensuring timely delivery of perishable meat products and maintaining the overall quality of the supply chain. Hence, considering road accessibility plays a significant role in determining the suitability of a site for meat processing and animal slaughtering facilities. Moreover, in order to find out better accessibility to the existing road, buffer zones have been created by taking distances between 20 m and 400 m from the existing major roads (LMA, 2000) to generate a suitable accessibility map. This accessibility map can help identify potential sites for meat processing and animal slaughtering facilities that are conveniently located near major roads. By analyzing the buffer zones, stakeholders can make informed decisions about the most suitable locations that will facilitate efficient transportation and minimize delays in delivering perishable meat products. Additionally, this approach ensures that the overall quality of the supply chain is maintained by reducing the risk of spoilage or contamination during transportation. Then the buffer distance zones have been categorized into four levels based on the level of proximity to the abattoir site. Accordingly, the low buffer distance ranked as highly suitable, whereas the longer buffer distances ranked as unsuitable (Figure 14). The categorization of buffer distance zones based on proximity to the abattoir site allows for efficient planning and allocation of resources. This ensures that meat products can be transported quickly and safely, reducing the chances of spoilage or contamination. By ranking longer buffer distances as unsuitable, potential risks and challenges associated with transportation can be effectively mitigated, further enhancing the overall quality of the supply chain. As a result, Table 9 assigns a rank value of four to highly suitable road buffers and a rank value of one to unsuitable road buffers. The ranking system allows for efficient planning and decision-making in terms of transportation routes. By prioritizing highly suitable road buffers, resources can be allocated effectively, reducing costs and optimizing delivery times. Additionally, the ranking system helps identify areas that may require additional infrastructure development or improvements to ensure a seamless supply chain for meat products.

Figure 14. Reclassified road map digitized from the structural plan of the town.

Table 9. Reclassified distance of main road networks.

Road(m)	Value	Level of Suitability
>1200	1	Unsuitable
800–1200	2	Moderately suitable
400–800	3	Suitable
<400	4	Highly suitable

3.3.7.2. Surface water

The abattoir site must not be located in close proximity to surface water (streams, rivers, lakes, or the sea) (EPA, 2002). The criterion is important from the point of view of both environmental and economic concerns because, in addition to causing pollution problems, it may require an efficient drainage system with high expenses. The streams/river factor was generated from the digital elevation model (DEM) using the ArcGIS spatial analyst extension of the hydrology module. Then it was buffered based on the 100-meter-distance standard criteria set by the EPA (2002) to locate abattoirs from critical environmental resources such as streams and rivers. This approach helps in identifying potential locations for abattoirs that are at a safe distance from streams and rivers, minimizing the risk of pollution and contamination. Additionally, it allows for better planning and allocation of resources, ensuring a more sustainable and cost-effective drainage system for the abattoirs. Thus, four buffer zones have been drawn around streams, and a relative suitability rank was assigned; buffers far from streams are more suitable, while buffers near streams are unsuitable. The area between 500 m and 1000 m is suitable for an abattoir site. The area greater than 1000 m is highly suitable for abattoir site selection and covers a large area of the study area (Figure 15 and Table 10). The selection of an abattoir site within the suitable areas can help minimize the potential impact on nearby streams and ensure better water resource management. Additionally, the large coverage of highly suitable areas beyond 1000 m provides ample options for locating abattoirs while maintaining a sustainable drainage system. Furthermore, choosing an abattoir site within the larger suitable areas can also mitigate potential conflicts with residential areas, as the distance helps to minimize noise and odor disturbances. Moreover, the extensive coverage of highly suitable areas beyond 1000 m allows for flexibility in designing and implementing the necessary infrastructure and facilities for efficient waste management and transportation logistics.

Figure 15. Reclassified map of the streams.

Table 10. Reclassified distance from streams.

Stream (m)	Value	Level of Suitability
0–100	1	Unsuitable
100–500	2	Moderately suitable
500–1000	3	Suitable
>1000	4	Highly suitable

3.3.8. Constraints

The constraints in this study include social services, high-tension lines, and boreholes. The abattoir should be situated at a significant distance from other areas. The focus is on alleviating possible negative impacts that abattoirs can pose on the surrounding environment and vice versa. The impact that the abattoir poses may manifest in the form of liquid wastes, solid waste, and airborne wastes (mainly disagreeable odors), a large potential for the transmission of zoogenic diseases, noise, traffic congestion, the attraction of animals (such as hyenas) and big birds, etc. Therefore, a buffer zone of a certain distance should be reserved around the abattoir. Therefore, each of these constraints was classified using the standard criteria by calculating the spatial analyst buffer zone distance. The optimal buffer zone of each factor was reclassified, and the resulting location was chosen as the suitable abattoir site (Figure 16 and Table 11). According to EPA (2002), LMA (2000), and NUPI experience, these guidelines recommend that the buffer zone around the abattoir should be at least 500 meters to minimize the impact of zoogenic diseases and noise on surrounding areas. Additionally, it is important to consider the proximity to residential areas and ensure that the abattoir is located away from densely populated regions to mitigate traffic congestion and potential disturbance caused by animals. Table 11 provides reclassified distances from social services, which further support the selection of the chosen location for the abattoir site. These distances take into account factors such as schools, hospitals, and recreational areas, ensuring that the abattoir is situated at a safe distance to prevent any potential negative effects on these facilities and their users. Figure 16 provides a visual representation of the suitability levels for the abattoir site based on the distances from social services. The map allows for easy identification of areas that are unsuitable, moderately suitable, suitable, and highly suitable for the abattoir location. This information can be used to make informed decisions about the best location for the facility, taking into consideration its potential impact on nearby social services.

Figure 16. Reclassified map of social services.

Table 11. Reclassified distances from social services.

social services (m)	Value	Level of Suitability
<300	1	Unsuitable
300–800	2	Moderately suitable
800–1500	3	Suitable
>1500	4	Highly suitable

3.3.8.1. Boreholes

The proximity of the abattoir site to a borehole is an important environmental criterion in abattoir site selection so that wells may be protected from the runoff and leaching of waste products from abattoirs. Some sources suggest that the location of abattoir sites should be 300 m away from the boreholes (LMA, 2000). This distance is recommended to prevent contamination of the groundwater and ensure the safety of drinking water sources. Additionally, maintaining a sufficient distance between abattoirs and boreholes can help minimize the risk of diseases spreading through contaminated water sources. To increase the importance of protecting the groundwater from pollution, in addition to its direct influence on the community. In each case of the above constraints, areas around all buffer zones are taken as the most suitable, and areas within the limit of the least buffer zones are taken as unsuitable for the abattoir site location. Many parts of the study area are highly suitable (Table 12 and Figure 17). These highly suitable areas can serve as potential locations for establishing abattoirs, as they are not only within the buffer zones but also have a low risk of groundwater pollution. This strategic placement of abattoirs can ensure the protection of both public health and the environment.

Figure 17. Reclassified map of the boreholes.

Table 12. Reclassified distances from boreholes.

Distance from borehole(m)	Value	Level of Suitability
<300	1	Unsuitable
300–800	2	Moderately suitable
800–1500	3	Suitable
>1500	4	Highly suitable

3.3.8.2. High-tension line

High-tension line: In order to avoid possible accidents that could be encountered because of big flying birds (e.g. scavengers) hovering over the abattoir, the site should be at least 500 meters away from high-tension lines (Environmental Protection Agency, 2002). These high-tension lines carry a significant amount of electricity, which poses a risk to both the birds and the workers at the abattoir. Additionally, the electromagnetic fields generated by these lines can disrupt the natural behavior and migration patterns of birds in the area. It is crucial to ensure that the site chosen for the abattoir is far enough from high-tension lines to minimize potential hazards. The distance between the abattoir and these lines should be carefully considered to create a safe environment for both birds and workers while also preserving the natural behavior and migration patterns of the local bird population. As the distance from the abattoir increased from the high-tension line, the suitability became more preferable (Table 13 and Figure 18). This information can be used to establish guidelines for selecting suitable sites for abattoirs, taking into account the safety of workers and the well-being of local bird populations. Additionally, conducting regular monitoring and assessment of the abattoir’s impact on the surrounding environment can help ensure that any potential hazards are promptly identified and mitigated.

Figure 18. Reclassified map of the high-tension line.

Table 13. Reclassified distances from the high-tension line.

Distance from the high-tension line (m)	Value	Level of Suitability
0–500	1	Unsuitable
500–1000	2	Moderately suitable
1000–1500	3	Suitable
>1500	4	Highly suitable

3.3.9. Calculation of the criteria and class weights

In order to generate abattoir sites, eight interrelated components of the environment were used as input data sets (factors). Accordingly, the selected input datasets were urban land use, road network, elevation, slope, borehole, streams, high-tension lines, and social services. Each of the factor maps was produced from a remote sensing image, a digital elevation model, and the structural plan of the town. Before combining them, the following procedures were taken place: first, rasterization was done for the vector data layers in order to produce similar data layers to perform GIS analysis, and second, standardization of each data set to a common scale of 1 to 4 was done in ArcGIS software. Weights must be assigned based on Satty’s Analytic Hierarchy Process (AHP) before the factors are combined. For each map, a pair-wise comparison matrix will be created using a nine-point importance scale (Table 14). Weighting is used to express the relative importance of each factor relative to another factor. The larger the weight, the more important the factor in overall utility. The overall utility score will be determined by multiplying the weights by the standardized values of each factor after they have been assigned. This process ensures that all factors are given appropriate consideration and that their contributions are properly weighted in the analysis. The final step involves combining the utility scores of each factor to obtain a comprehensive evaluation of the data sets on a common scale of 1 to 4.

Table 14. Pair-wise comparison, 9-point weighting scale.

1/9	1/7	1/5	1/3	1	3	5	7	9	2,4,6,8
Extremely	Very Strong	Strongly	Moderately	Equally important	Moderately	strongly	Very strongly	Extremely	Intermediate value
Less Important				More Important					Equal

Source: (Saaty, 1980), referenced in (Malczewiski, 1999).

The primary objective of calculation in the AHP procedure is the Eigen vector corresponding to the matrix’s biggest Eigen value. In other words, if one factor is preferred over another, its eigenvector component will be bigger than that of the other. Each element in the eigenvector represents the relative priority of the related factor (Figure 19). The method used to determine the eigenvalue and subsequent eigenvector is the sum-product approach. Tables 15, 16, and Figure 19 illustrate the process of creating a pairwise comparison matrix, in which the sum of each column represents a value. The appropriateness model is created using the weights that AHP ultimately determined. To examine thsary to determine the degree of consistency that has been used in developing the judgments. In AHP, an index of consistency, known as the consistency ratio (CR), is used to indicate the probability that the matrix judgments were randomly generated.

Figure 19. Abattoir site suitability analysis model builders.

Table 15. Pair-wise comparison of weighting scale.

Factor	LULC		Stream	Slope	Elevation	Road	Borehole		High-tension line	Social service
LULC	1	2		3	2	2	3	3		2
Stream	1/2	1		3	3	2	2	3		3
Slope	1/3	1/3		1	2	2	2	2		3
Elevation	1/2	1/3		1/2	1	1/3	2	2		3
Road Network	1/2	1/2		1/2	3	1	2	2		3
Borehole	1/3	1/2		1/2	1/2	1/2	1	2		2
High-tension line	1/3	1/3		1/2	1/2	1/2	1/2	1		3
Social service	1/2	1/3		1/3	1/3	1/3	1/2	1/3		1
Total column sum	4.00	5.33		9.33	12.33	8.66	13.00	15.33		20.00

Source: Extracted from pair-wise comparison of weighting scale.

Table 16. Normalized pair-wise comparison matrix.

Normalized value	LULC	Stream	Slope	Elevation.	Road	Borehole	High-tension line	Social service	sum
LULC	0.25	0.373	0.321428	0.162162	0.2307	0.2307	0.1956	0.1	1.863
Stream	0.125	0.1875	0.321428	0.243243	0.2307	0.15384	0.1956	0.15	1.607
Slope	0.083	0.0625	0.107142	0.162162	0.2307	0.15384	0.1304	0.15	1.079
Elevation	0.125	0.0625	0.0535714	0.0810810	0.03846	0.15384	0.1304	0.15	0.795
Road Network	0.125	0.0937	0.053571	0.243	0.1153	0.15384	0.1304	0.15	1.064
Borehole	0.125	0.0937	0.0535714	0.04054	0.05769	0.07692	0.1304	0.1	0.677
High-tension line	0.125	0.0625	0.0535714	0.04054	0.05769	0.03846	0.0652	0.15	1.075
Social service	0.833	0.0625	0.0357142	0.027027	0.03846	0.03846	0.0217	0.05	1.103

Source: extracted from a normalized pair-wise comparison matrix.

Calculating Consistency Ratio (CR)

$\mathrm{C}\mathrm{R}=\mathrm{C}\mathrm{I}/\mathrm{R}\mathrm{I}$

Where $\mathrm{C}\mathrm{I}=\lambda -\mathrm{n}/\mathrm{n}-1$

RI = Random consistency index

n = Number of criteria.

λmax is the priority vector multiplied by each column total. Where RI is the average of the resulting consistency index depending on the order of the matrix given by Saaty (1980), and the consistency index (CI) is defined as:

(1) $CI=\frac{\lambda max-1}{n-1}$(1)

Where λmax is the principal Eigen value of the matrix and n is the order of the matrix.

The AHP also provides measures to determine the inconsistency of judgments mathematically. The CR, which is a comparison between the consistency index (CI) and random consistency index (RI), can be calculated using the following formula:

(2) $\mathit{C}\mathit{R}=\frac{CI}{RI}$(2)

In this process, experts’ opinions were asked to calculate the relative importance of the factors and criteria involved. It is recommended that the consistency ratio present values below 0.1.

From the calculation, the value of λ_{max =} 8.73204

$\mathbf{C}\mathbf{I}=\frac{\lambda \mathrm{m}\mathrm{a}\mathrm{x}-1}{\mathrm{n}-1}$

$\mathbf{C}\mathbf{I}=\hspace{0.17em}8.73204-1/8-1$

$\mathrm{C}\mathrm{I}=-\mathbf{0.03}$

From Table 17, the factor number is 8.

Table 17. Random index value.

Factor number	3	4	5	6	7	8	9	10	11	12	13	14	15
Randomness value	0.58	0.9	1.12	1.24	1.32	1.41	1.45	1.51	1.52	1.54	1.56	1.58	1.59

Source: (Saaty, 1980).

RI = 1.41

$\mathrm{C}\mathrm{R}=\frac{\mathrm{C}\mathrm{I}}{\mathrm{R}\mathrm{I}}$

$\mathrm{C}\mathrm{R}=0.1045782/1.41=\mathbf{0.07}.$

$\mathrm{C}\mathrm{o}\mathrm{n}\mathrm{s}\mathrm{i}\mathrm{s}\mathrm{t}\mathrm{e}\mathrm{n}\mathrm{c}\mathrm{y}\mathrm{R}\mathrm{a}\mathrm{t}\mathrm{i}\mathrm{o}=0.07\mathrm{w}\mathrm{h}\mathrm{i}\mathrm{c}\mathrm{h}\mathrm{i}\mathrm{s}\mathrm{a}\mathrm{c}\mathrm{c}\mathrm{e}\mathrm{p}\mathrm{t}\mathrm{a}\mathrm{b}\mathrm{l}\mathrm{e}$

CR* was also calculated and found to be 0.07 (7%), which is acceptable to be used in the site suitability analysis. For the individual factor maps to be combined in a weighted overlay in the ArcGIS environment, the computed Eigen vector is used as a coefficient. This weighted overlay analysis allows for the integration of multiple factors and their relative importance in determining site suitability (Table 18). By assigning weights to each factor based on the computed Eigen vector, the resulting map can provide a comprehensive evaluation of potential sites for the desired purpose. The use of ArcGIS further enhances the accuracy and efficiency of this analysis by providing a robust platform for spatial data manipulation and visualization.

Table 18. Classification of factor values and their weights obtained after pair-wise comparison.

Factor	Class	Value	Level of Suitability	Influence (%)
Urban land use	Built-Up, Stream, and Wetland	1	Unsuitable	0.24
	Forest	2	Moderately suitable
	Agriculture and Vegetation	3	Suitable
	Barren land	4	Highly suitable
Slope (%)	>30	1		0.201
	21–30	2	Moderately suitable
	11–20	3	Suitable
	2–10	4	Highly suitable
Elevation (m)	1760–1838	1	Unsuitable	0.135
	1720–1760	2	Moderately suitable
	1680–1720	3	Suitable
	1640–1680	4	Highly suitable
Distance from the road (m)	>1200	1	Unsuitable	0.099
	800–1200	2	Moderately suitable
	400–800	3	Suitable
	<400	4	Highly suitable
Stream (m)	<100	1	Unsuitable	0.13
	100–200	2	Moderately suitable
	300–400	3	Suitable
	>400	4	Highly suitable
Distance from high tension (m)	<500	1	Unsuitable	0.08
	500–1000	2	Moderately suitable
	1000–1500	3	Suitable
	1500–2000	4	Highly suitable
Distance from the social services (m)	<300	1	Unsuitable	0.069
	300–800	2	Moderately suitable
	800–1500	3	Suitable
	>1500	4	Highly suitable
Distance from the borehole (m)	<300	1	Unsuitable	0.050
	300–800	2	Moderately suitable
	800–1500	3	Suitable
	>1500	4	Highly suitable

3.3.10. Integration of criteria maps and preparation of the final suitability map

At this stage, all the factor layers are prepared to be combined, keeping in mind the end goal of identifying a suitable abattoir location in the study area. If all data sets were equally important, it could be possible to simply combine them. From the principal eigenvector calculation, the relative significance of every parameter was determined. Hence, the higher the weight, the more influence a particular factor will have on suitable site generation. Accordingly, the factor layers were combined by applying the following equation in the raster calculator of the spatial analyst extension in the ArcGIS environment. It was done systematically using the ArcGIS model builder (Figure 19).

(3) $[\mathrm{L}\mathrm{u}\mathrm{l}\mathrm{c}]\ast 0.24+[\mathrm{s}\mathrm{l}\mathrm{o}\mathrm{p}\mathrm{e}]\ast 0.21+[\mathrm{e}\mathrm{l}\mathrm{e}\mathrm{v}\mathrm{a}\mathrm{t}\mathrm{i}\mathrm{o}\mathrm{n}]\ast 0.13+[\mathrm{r}\mathrm{o}\mathrm{a}\mathrm{d}]\ast 0.09+[\mathrm{H}\mathrm{i}\mathrm{g}\mathrm{h}\mathrm{t}\mathrm{e}\mathrm{n}\mathrm{s}\mathrm{i}\mathrm{o}\mathrm{n}\mathrm{l}\mathrm{i}\mathrm{n}\mathrm{e}]\ast 0.08+[\mathrm{s}\mathrm{t}\mathrm{r}\mathrm{e}\mathrm{a}\mathrm{m}\mathrm{s}]\ast 0.13+[\mathrm{s}\mathrm{o}\mathrm{c}\mathrm{i}\mathrm{a}\mathrm{l}\mathrm{s}\mathrm{e}\mathrm{r}\mathrm{v}\mathrm{i}\mathrm{c}\mathrm{e}]\ast 0.069+[\mathrm{B}\mathrm{o}\mathrm{r}\mathrm{e}\mathrm{h}\mathrm{o}\mathrm{l}\mathrm{e}]\ast 0.05=\mathrm{a}\mathrm{s}\mathrm{u}\mathrm{i}\mathrm{t}\mathrm{a}\mathrm{b}\mathrm{l}\mathrm{e}\mathrm{m}\mathrm{a}\mathrm{p}\mathrm{o}\mathrm{f}\mathrm{t}\mathrm{h}\mathrm{e}\mathrm{a}\mathrm{b}\mathrm{a}\mathrm{t}\mathrm{t}\mathrm{o}\mathrm{i}\mathrm{r}$(3)

The site suitability map has been classified into four classes: highly suitable, suitable, moderately suitable, and unsuitable. Table 19 shows that 1.27% of the study area covers a highly suitable area, whereas a total of 28.42% of the area is suitable, 21.54% of the area is moderately suitable, and the unsuitable area covers 48.75% of the study. This classification provides a clear understanding of the distribution of site suitability across the study area. It allows for targeted decision-making and the prioritization of resources based on the varying levels of suitability identified.

Table 19. Statistical analysis for the abattoir site suitability map.

Suitability level	Value	Area(ha)	Percent (%)
Unsuitable	1	3106.43	48.75
Moderately suitable	2	1372.77	21.54
Suitable	3	1810.86	28.42
Highly suitable	4	81.11	1.27

The most appropriate site was situated at the north-west, north-east, and south-east of the town, over bare land and agricultural areas. Planners and decision-makers can get useful information about the possible locations of abattoir sites using this methodology. This methodology takes into account factors such as proximity to transportation routes, availability of utilities, and potential impact on surrounding communities. By considering these factors, planners and decision-makers can make informed choices about the most suitable location for an abattoir that minimizes potential disruptions and maximizes efficiency.

As can be seen from the suitability map (Figure 20), the highly suitable (1.27%) areas are mainly located in the south-east, north-east, and north-west. These areas cover mainly agricultural and bare land uses. Currently, these areas are waiting for the distribution of specific urban land use developments. The suitability map also indicates that the remaining areas, which are less suitable for urban land use (98.73%), are scattered throughout the region. These areas include forests, wetlands, and protected areas that are important for ecological preservation. Therefore, careful consideration should be given to balancing urban development with environmental conservation in these regions. The suitable areas are located on the periphery of the built-up area. These are bareland, forested, agricultural, and vegetated areas devoid of urban settlements.

Figure 20. Suitability map of the abattoir.

The highly suitable, suitable, and moderately suitable areas have an appropriate site for the development of facilities. The areas are also free from any conflicts or restrictions on usage. The unsuitable areas for abattoir site selection are also located in the developed part of the town, wetland, and streams (48.75%). The suitability of an abattoir site can be expressed in terms of its existing features. Figure 21 shows the composite suitability of the constraint map and the factor maps. The areas are labeled as highly suitable, suitable, moderately suitable, and unsuitable. It is still possible to make further suitability differentiation among these areas. Those parts of the selected areas that are near the existing roads are more suitable than those located further, as far as only the road factor is considered. However, other factors such as proximity to residential areas, access to utilities, and environmental impact should also be taken into account when determining the overall suitability of the abattoir site. Additionally, conducting a thorough analysis of traffic patterns and potential future road developments could provide valuable insights into the long-term viability of the selected areas.

Figure 21. Suitability map of an abattoir overlaid by factor layers.

The constraints are usually regulations (environmental, land use, etc.), which are legal constraints in essence. Obviously, this is a constraining criterion that immediately limits the specified area for development. That is, such constraining criteria are considered legal constraints and cannot be compromised. To prioritize the future land uses of the study areas, the choice of two alternative sites moderately suitable and suitable areas is relatively more suitable for residential development than for locating an abattoir. If the abattoir is sited either within moderately suitable or suitable, the likelihood that it will be relocated earlier than expected (because of residential pressure or encroachment) would be greater. The highly suitable area, on the other hand, is less suitable for residential development, and hence it is selected as the best area for the intended abattoir. This area is located near the boundary of the town and is also located in the south-east, north-east, and north-west of urban land use. It can therefore be observed that, being located within this area, the abattoir will have a prolonged life before it can be relocated. Additionally, the selected area is relatively isolated from residential neighborhoods, minimizing the potential for conflicts between the abattoir and nearby residents. This isolation also allows for easier transportation of livestock and products without disrupting urban traffic flow. Overall, choosing this highly suitable area ensures the long-term viability and sustainability of the abattoir within the town’s urban planning framework.

3.3.11. Cattle markets

Cattle markets are usually recommended to be located close to the abattoir so that purchased cattle could immediately be taken to the abattoir without having to cross the town. This reduces possible traffic problems that would otherwise be created and cattle fattening lots; this type of investment activity exists in most towns in the country. In addition, the proximity of cattle markets to abattoirs also ensures the freshness and quality of the meat, as it can be processed and distributed more efficiently. Moreover, the presence of cattle-fattening lots in most towns indicates a thriving livestock industry, providing employment opportunities and contributing to the local economy. The cattle are usually fattened to be sold later. This practice not only benefits the farmers and investors involved but also supports the overall economic growth of the country. Furthermore, the demand for cattle meat remains high, both domestically and internationally, making cattle fattening a lucrative business opportunity for many. Thus, it is compatible both with the abattoir and the cattle market. Additionally, locating cattle markets near abattoirs allows for efficient transportation and minimizes stress on the animals. This proximity also facilitates the coordination of logistics between the market and abattoir, ensuring a smooth flow of operations. Moreover, this setup promotes economic growth in rural areas by attracting investments in cattle-fattening lots and supporting local farmers.

Generally, a highly suitable area of abattoir can be summarized in terms of the specific objectives set at the beginning of the study. In other words, locating the abattoir at this site ensures minimizing the impact of the abattoir on the surrounding environment and reducing the impact of nearby activities on the abattoir. This can be achieved by considering factors such as proximity to residential areas, the availability of proper waste management systems, and adherence to strict environmental regulations. Additionally, the suitable area should also take into account the accessibility of transportation routes for both incoming livestock and outgoing products to ensure efficient operations.

3.3.12. Selecting the final site and its criteria

In this section, we identify the final site among highly suitable sites according to criteria and area. The best locations for a new abattoir have been identified. The finding in the weighted overlay has shown that only 81.11 hectares of the total study area were found highly suitable for the abattoir site (Figure 21). From the analysis, the available high-potential site area coverage was significant enough to obtain enough parcels of land for an abattoir. All the locations in the filtered optimal area layer are highly suitable. By examining the Filtered optimal areas layer with all factors and determining the final site, to select the final site, the criteria are first considered and compared to each other. In the study area, there are five selected sites, but from these five selected sites, the final site must be filtered and selected. The filtering process will involve evaluating factors such as proximity to transportation routes, availability of utilities, and compliance with zoning regulations. Additionally, the final site selection will take into account the potential impact on the surrounding community and environmental considerations. Once these criteria have been thoroughly assessed, the most suitable site for the abattoir will be chosen from the initial five selected sites.

Finally, a number of factors can be taken into consideration to decide where the abattoir will ultimately be built (Figure 22 and Table 20). These factors include the availability of suitable land, proximity to livestock farms, access to transportation networks, and compliance with environmental regulations. Additionally, the economic impact on the local community and potential job creation should also be considered in the decision-making process.

Figure 22. Optimal filtered final selected site.

Table 20. Comparison of the various requirements for the abattoir’s final location.

no	Criteria	Site-1	Site-2	Site-3	Site-4	Site-5
1	Area(ha)	1.74	1.51	1.23	7.9	1.93
2	Land use and land cover	Barren land	Barren land	Barren land and agricultural	Barren land	Barren land And forest
3	Slope	2–20	2–10	2–10	2–20	2–10
4	Distance to the Road	High suitable but touched one side by road	High suitable	High suitable	High and suitable, but crossing the road	High suitable
5	Elevation	suitable/High suitable	High suitable	High suitable	High suitable	suitable
6	Distance from the stream	High suitable	High suitable	High suitable	High suitable	High suitable
7	Distance from the high-tension line	High suitable	suitable	suitable	High suitable	High suitable
8	Distance from the borehole	High suitable	High suitable	High suitable	High suitable	High suitable
9	Distance from social service	High suitable	High suitable	High suitable	High suitable	High suitable
10	Distance from town	Far away from town	Far away from town	Far away from town	Far away from town	On good distance from town
Suitability rank		4^th	2^nd	3^rd	5^th	1^st

In Table 20, records of measured attribute values for each candidate were obtained. These measured attributes of each candidate site were used for later prioritization and ranking of their suitability for abattoir construction with respect to evaluation criteria (land use and cover, size, slope, elevation, distance to town, distance to road, distance to borehole, distance to stream, distance to social service, and distance to high tension line). As seen in Table 20, the criteria are in conflict with each other. For instance, site 2 and site 5 candidate sites are most preferable in all criteria except distance from town. In terms of land use and cover, size, slope, elevation, distance to road, distance to borehole, distance to stream, distance to social service, and distance to high tension line, sites 2 and 5 are highly suitable for abattoir construction (Figure 22). However, sites 2 and 5 are located farther away from the town compared to other candidate sites. This may pose logistical challenges in terms of transportation and accessibility for both workers and customers. Therefore, careful consideration should be given to balancing the preference for all criteria and the practicality of site location in order to make an informed decision on the best site for abattoir construction. However, when considering their proximity to the town, these sites fall short compared to other candidates.

Sites 1 and 4 are not preferred due to intersecting roads. According to LMA (2000), the site should preferably lie on agricultural or empty land for the purpose of reducing site acquisition costs. Additionally, site selection should prioritize locations that are easily accessible and have sufficient infrastructure for future development. It is also important to consider the proximity to potential customers or target markets for the project’s success. Location 5 was selected as a result because it has a forest and open space on one side (Figure 23). This provides a natural buffer and ensures that there will be no future development that could potentially obstruct the project. Furthermore, Location 5 is conveniently located near major highways and has existing utilities, making it an ideal choice for the project’s future growth and accessibility. The legal separation from an abattoir to a town border is 3.5 km, so the final site is acceptable (EPA. 2002; Environmental Protection Agency, 2002), and the final site capacity is 1.94 hectares. Considering the environmental impact of the project is also crucial when selecting a site. It is important to assess any potential risks or conflicts with nearby ecosystems or protected areas. Additionally, conducting a thorough analysis of the soil quality and drainage capabilities of the chosen site can help ensure its suitability for agricultural purposes. The size of the selected site (1.94 hectares) should be able to accommodate the necessary facilities and infrastructure for the project’s development. To make sure that the project’s operations do not adversely affect the forested area nearby, a thorough environmental impact assessment is essential. It would also be crucial to take into account any possible zoning or regulatory limitations in the region to guarantee adherence to local laws and regulations. The final location chosen for the slaughterhouse is preferable because, according to the National Urban Planning Institute, an abattoir site capacity larger than or equivalent to one hectare is preferred. This ensures that there is ample space for the necessary infrastructure and facilities required for an abattoir to function efficiently. Additionally, a larger site capacity allows for potential expansion or future upgrades to meet the growing demands of the industry.

Figure 23. The final selected suitable site for the abattoir.

4. Conclusions and recommendations

4.1. Conclusions

Abattoirs are critical urban functions that provide domesticated animal processing services to the towns or urban areas they serve. These facilities play a crucial role in ensuring the availability of meat products for consumption. Additionally, abattoirs adhere to strict regulations and guidelines to ensure the safety and quality of the processed meat. A definitive motivation behind establishing abattoirs is to provide cleaner and more hygienic butchering services, to guarantee appropriate utilization of animal products, to produce income for the service rendered, and to reduce impacts on the environment by controlling the waste disposal system. Abattoirs play a crucial role in the overall food supply chain by efficiently processing and distributing meat products to meet the demands of consumers. Furthermore, these facilities contribute to the economy by creating job opportunities and supporting local businesses involved in the meat industry. Abattoirs have some essential elements that require the search for a unique location for them. Such a location should satisfy some specific objective, including minimizing the undesirable effects that the abattoir can pose on the encompassing environment and vice versa, ensuring the accessibility of basic facilities essential for the proper functioning of the abattoir, and so on. GIS and WLC are significant tools that can support decision-makers in finding the best possible abattoir sites.

The GIS analysis requires gathering data from various sources in different formats to create a complete, uniform database. Consequently, the GIS data should be updated consistently, keeping in mind the end goal of mirroring the present circumstances of the area under investigation. Remote sensing data can help provide updated information about the study area. Remote sensing data can provide valuable information such as land cover, vegetation density, and topography, which are crucial factors in determining suitable abattoir sites. Additionally, remote sensing techniques can also aid in monitoring and assessing the environmental impact of potential abattoir locations, ensuring sustainable practices are followed. Likewise, it can help the decision-maker monitor the examined area using different dates of satellite images to separate the urban land use and land cover classes, for instance. By analyzing land cover, vegetation density, and topography, decision-makers can identify areas that are most suitable for abattoir sites based on their environmental impact. Remote sensing techniques provide a valuable tool for monitoring and assessing these potential locations, allowing for the implementation of sustainable practices. Furthermore, the use of satellite images taken at different dates enables decision-makers to accurately distinguish between urban land use and land cover classes, aiding in the overall assessment process.

The findings have shown the ability of GIS and remote sensing to be genuine tools for analyzing the criteria for decision support. The analysis has taken land use and cover, slope, elevation, proximity to main roads and streams, and environmental constraints as determining factors in order to find an appropriate site for an abattoir. By incorporating GIS and remote sensing technologies, decision-makers can effectively evaluate various factors simultaneously and make informed decisions regarding the selection of an ideal abattoir location. These tools enable a comprehensive assessment of the spatial characteristics and constraints, ensuring that the chosen site meets all necessary requirements for sustainable and efficient operations.

The three candidate sites were suggested in light of the methodology and available data applied in this research. The results of 1.27%, 28.42%, and 21.54% have demonstrated that three sites were chosen as highly suitable, suitable, and moderately suitable, respectively. These places are far from any water sources, and different factors were taken into consideration in the analysis. The places are located in different parts of the town. The most appropriate site was situated at the north-west, north-east, and south-east of the town, over bare land and agricultural areas. Planners and decision-makers can get useful information about the possible locations of abattoir sites using this methodology. Particularly, the site ranking process allows for easy rearrangement of the criteria weights in the case that a sensitivity analysis is required. In any case, defining detailed and standard criteria by the Environmental Agency that agree with the local conditions can enhance the outcome of GIS models utilized for the purpose of finding an appropriate abattoir site. These criteria should take into consideration factors such as proximity to residential areas, access to transportation routes, and the availability of utilities. Additionally, involving local communities and stakeholders in the decision-making process can help ensure that the chosen abattoir site aligns with their needs and concerns.

Generally, the suggested areas comply with the minimum requirements of the abattoir site selection. However, any GIS model is limited to the available data, and in this study, different parameters were considered. These parameters include proximity to residential areas, access to transportation routes, availability of utilities, and compliance with environmental regulations. By considering these factors, the GIS model aims to provide a comprehensive analysis for abattoir site selection. Nonetheless, it is important to note that the final decision should also involve stakeholder consultation and further feasibility studies to ensure the long-term success of the chosen site. Therefore, any additional information, such as wind direction, land price, detailed soil data, and other social and economic factors, can enhance the outputs of the GIS model and provide more realistic results. However, getting public agreement on any candidate area is a must and cannot be avoided. Therefore, the local community should participate in the selection process for the abattoir site to avoid any opposition in the future. Engaging the local community in the decision-making process will not only address their concerns and potential opposition but also foster a sense of ownership and acceptance towards the chosen abattoir site. Furthermore, conducting thorough environmental impact assessments and considering the proximity to residential areas and infrastructure will contribute to a well-informed decision that takes into account both social and environmental factors.

4.2. Recommendations

The study demonstrated the appropriateness and necessity of using a GIS for land suitability analysis in planning urban growth in the Ethiopian context. The findings highlighted the potential of GIS in effectively identifying suitable areas for urban development based on various factors such as infrastructure availability, environmental considerations, and population density. Furthermore, the study emphasized the importance of incorporating local knowledge and community engagement in the decision-making process to ensure sustainable and inclusive urban growth in Ethiopia. The following suggestions for additional system implementation are made:

1. The GIS-based multi-criteria evaluation technique is simple and flexible, and it can be used to look into possible areas for urban growth and promote transparent participation in the urban decision-making process. Planning professionals must therefore practice using GIS in order to build an appropriate strategy for the town’s sustainable growth.

2. For municipalities that need one abattoir, the abattoir site suitability model created in this study is anticipated to be implemented. Additional issues, particularly those related to the spatial distribution of the abattoirs, must be taken into account when more than one abattoir is necessary.

3. To address the location issues related to municipal abattoirs, this study has been planned. Depending on the nature and complexity of such abattoirs, additional considerations may need to be taken into account for export abattoirs, which rely on the country’s future economic growth.

4. There are different places identified as highly suitable, and among these, the urban planner of the municipality of the town has to determine which area is best based on size and criteria rather than the selected final site.

5. It is recommended to update the GIS database regularly to reflect changes in the study area and ensure the accuracy of the analysis. Remote sensing data can be utilized to provide up-to-date information about the area, such as land cover and vegetation density.

6. Further studies should be conducted to determine the economic feasibility of the proposed abattoir locations and their financial viability. This can involve a cost-benefit analysis of the proposed abattoir sites to determine which location provides the most economic benefits.

7. Stakeholder consultation should be conducted throughout the abattoir site selection process to ensure that the selected location aligns with the needs and concerns of the local community. The involvement of communities in the decision-making process fosters a sense of ownership and acceptance of the chosen site.

8. Environmental impact assessments should be conducted to determine the potential environmental impact of the proposed abattoir sites. Risk assessments and mitigation measures should be developed to minimize any adverse impacts on the environment and public health.

9. Further research can be conducted to develop more comprehensive criteria for abattoir site selection, incorporating social, economic, and environmental factors. This can involve stakeholder consultation and expert opinions to develop more complex and accurate site selection models.

Overall, the use of GIS and multi-criteria evaluation techniques can help municipalities make informed and sustainable decisions regarding abattoir site selection. It is essential to consider various factors, including economic viability, community needs, and potential environmental impacts, when selecting an abattoir location. Ongoing monitoring and stakeholder engagement can also help ensure the continued success and sustainability of the chosen site.

4.3. Future research perspectives

Further research can expand upon the findings of this study and explore more detailed criteria for abattoir site selection. This could involve investigating the impact of different geographical factors, such as proximity to transportation routes or the availability of utilities, on the efficiency and sustainability of abattoir operations. Additionally, examining the social and environmental implications of abattoir placement in relation to local communities and ecosystems would provide a comprehensive understanding for future decision-making processes. Additionally, analyzing the economic benefits of the proposed abattoir sites can provide more insight into the financial viability of the project. It would also be beneficial to conduct social impact assessments to gauge the effects of abattoirs on nearby communities. Furthermore, incorporating emerging technologies such as machine learning algorithms and big data analytics can enhance GIS models and improve site selection accuracy. These technologies can help analyze various factors, such as transportation networks, environmental impacts, and market demand, allowing for a more comprehensive evaluation of potential abattoir sites. Moreover, considering the long-term sustainability of the chosen sites by assessing factors like water availability and waste management systems can ensure the abattoirs operate in an environmentally responsible manner.

Moreover, future research can investigate the impact of climate change on abattoir operations and identify strategies to mitigate adverse effects. Climate change can affect meat production by altering animal behavior and increasing the occurrence of disease outbreaks, among other factors. Furthermore, climate change can negatively impact the quality and availability of water resources, which are crucial to abattoir operations. Therefore, implementing sustainable practices that consider climate change can improve the resilience of abattoirs and ensure their long-term success. One strategy to mitigate the adverse effects of climate change on meat production is to invest in research and development for breeding animals that are more resilient to changing environmental conditions. Additionally, adopting sustainable water management practices, such as implementing efficient irrigation systems and recycling wastewater, can help abattoirs maintain a reliable water supply despite potential disruptions caused by climate change. By proactively addressing these challenges, abattoirs can adapt to the changing climate and continue to meet the demand for meat while minimizing their environmental impact.

Finally, future research can assess the feasibility of alternative meat production methods such as plant-based meats and cultured meat. These alternative meat products have a lower environmental impact than traditional animal agriculture, and their production does not require the establishment of abattoirs. Thus, assessing the potential of these technologies can provide alternative solutions to traditional meat production and offer new insights into urban planning and sustainability. Additionally, future research can also explore the potential economic benefits of alternative meat production methods. By analyzing market demand and consumer preferences for plant-based meats and cultured meat, policymakers and businesses can make informed decisions about investing in these technologies. This research can contribute to the development of a more sustainable and profitable food industry that aligns with the growing global concern for environmental conservation.

Authors’ contributions

Ajitesh Singh Chandel significantly improved the research’s conceptual framework, providing guidance and supervision throughout the investigation. His meticulous scrutiny and extensive subject-matter expertise ensured the authenticity and accuracy of the findings, while also fostering a comprehensive understanding of the study’s implications and applications.

Kenenu Asefa Dedecha contributed to the study’s conceptualization, drafted the manuscript, formulated methodology, conducted data analysis, and conducted field investigation. He collaborated with fellow scholars to ensure the precision and reliability of the findings.

Degu Bekele meticulously scrutinized and refined the manuscript, ensuring accurate data analysis and interpretation. His expertise in data analysis identified key patterns, enhancing the study's quality. His ability to communicate complex ideas made the study accessible to a wide audience, and his commitment to staying current with field advancements ensured the use of relevant methodologies.

Acknowledgments

The researchers express their gratitude to the administrative authorities of the town of Adola Woyu for their cooperation and permission to conduct the study. Additionally, the author would like to thank the municipal authorities, city beautification office, and municipal administrators of Adola Woyu Town for their support in carrying out the research. Their support and cooperation were instrumental in ensuring the smooth execution of the study. The researchers also appreciate the valuable insights and assistance provided by the local community members, whose participation greatly enriched the research findings.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data supporting the results of this study are available at reasonable request from the corresponding author.

Additional information

Funding

The authors received no financial support for their research, authorship, or publication of this article.