Analysis of spatiotemporal dynamics urban sprawl using Landscape metrics and Shannon entropy: A case of Adama city, Ethiopia

Abstract

Urban sprawl is a major challenge in managing urban growth, particularly in developing countries experiencing rapid urbanization. The study focuses on analyzing the spatiotemporal dynamics of urban sprawl in Adama city from 2000 to 2022 using Landscape metrics and Shannon entropy. The research utilized satellite datasets (Landsat TM, ETM+, and OLI/TIRS) and applied supervised classification techniques to create land use and land cover (LULC) maps for three time points. Post-classification comparison was conducted to examine changes in LULC over time. The study also investigated different types of urban growth by analyzing the spatial relationship between pre-growth and newly developed components. Spatial metrics and Shannon's entropy were utilized to quantify the extent of urban sprawl. The findings reveal that urbanization has negatively impacted agricultural and vegetation land, resulting in significant conversions to built-up areas in Adama city. Between 2000 and 2022, a substantial amount of agricultural land (5893 hectares) and vegetation land (4038 hectares) were transformed into built-up areas. Over the 22-year period, there has been a gradual increase in urban sprawl, with the area of built-up areas expanding from 3064.34 hectares in 2000 to 4788 hectares in 2022. The study identified various types of urban growth, including outlying, edge expansion, and infilling, which contributed to the overall urban area. The analysis indicates the presence of sprawl with high dispersion and heterogeneity, gradually spreading from the central business district (CBD) toward the periphery. The study highlights the accelerated spatiotemporal dynamics of urban sprawl in Adama city over the past 22 years. The city is experiencing rapid and unexpected expansion, which is projected to continue in the coming decades. To address this issue, urban planners must proactively develop and implement effective strategies that can effectively manage the rate of urban sprawl.