Urban sprawl characterization and its impact on peri-urban agriculture in Sidi Bel Abbes, Algeria, using multi-date landsat imagery

Identifying and characterizing the spatiotemporal dynamics of urban areas is mandatory in many disciplines, e.g., in environmental studies, infrastructure, and agriculture. The current research work investigates the overall trends of urban development and agricultural land changes of Sidi Bel Abbes city, for the years 1987, 1999, 2009 and 2019. To this end, Landsat archives have been considered due to its excellent temporal coverage, appropriate spatial dimension for urban characterization, and free data access. Multiple classifiers decision fusion technique was performed to characterize the spatial distribution of the built-up areas followed by agricultural land changes estimation through the Normalized Difference Vegetation Index. The results reveal that over the last three decades, a significant increase of built-up lands has been settled at the expense of peri-urban agriculture where the net-growth rate (%) of built-up areas and agricultural land per year between 1987 to 1999, 1999 to 2009 and 2009 to 2019 were + 4.2, + 2.83, + 2.11 and -1.66, -0.94, -0.69 respectively. The multi-temporal assessment of urban change and orientation permitted the identification of slow (southeast) and fast (north-east) sprawling areas. In addition, to understand the built-up expansion effects on the agricultural land-cover, urban sprawl was analyzed and the results show that the settlement areas generally increased in the whole study period, which was around 39.01% of the total area (7077 ha) and similarly, peri-urban agriculture areas decreased by approximately 32% from the arable lands (4648 ha).