GIS and Remote Sensing Based Suitability Analysis of Urban Development The Case of Jimma City, Western Ethiopia

Abstract

Site suitability analysis for specific project is the preliminary tasks in the context of modern urban land use planning and development. However, site analysis by its nature is the complex process. It involves consideration of multi-criteria decision making limited not only to physical condition of urban land-uses, but more attention should be given to integrate socio-economic and environmental factors. GIS based Multi-Criteria Evaluation (MCE) and Analytical Hierarchy Process (AHP) provides a wide range of powerful tools capable to transform, combine geospatial data with value judgments among conflicting criteria along with sets of alternatives. Nine factors such as landsatland-use/land-covers, river, slope, elevation, geomorphology, soil, road, aspect, and proximity to urban center were evaluated and prioritized as per judgment of urban planning experts. The influencing weight among factors has been computed using Analytic Hierarchy Process (AHP) in IDRISI 32 software. The overall Consistency Ratio (CR) of the module was 0.02% and fulfilled the tolerable threshold (CR ≤ 0.10). Finally, the Weighted Linear Combination (WLC) function of ArcGIS model builder has been applied to generate suitability map. Finding of the study clearly reveals that the city has dramatically grown in all directions in the last two decades Built-up area increased a lot in the last 20 years by consuming considerable amount of other land-use/land cover types. Result from suitability analysis shows that from the total area of Jimma City, about 1070.5ha (10.2%) of the land is grouped under suitable site; whereas majority of the city 6712.2ha (63.8%) falls under moderately suitable for urban development became categorized under suitable site for urban development. The critical importance of land for specified uses should be known either physical or economic suitability.