Remote Sensing Change Detection using ArcGIS: A Comparative Study Of Methods Applied to Urban Expansion in Baghdad City

Abstract

Third world countries often suffer from poor urban planning and unregulated construction including the conversion of agricultural land into residential commercial or industrial areas. Middle Eastern countries in particular are among the leaders in this trend actively transforming farmland into residential zones. This study focus on comprehensive evaluation of three methods of remote sensing techniques change detection within the ArcGIS program environment specifically to study urban expansion in Baghdad province over a 20-year period (2004–2024). The goal of our study identifies the basic preprocessing steps necessary to remove external influences and examines the theoretical foundations of image subtraction image ratio and subsequent classification followed by their practical application using satellite image analysis tools and the spatial analyzer in ArcGIS software. Image subtraction  methods are conceptually simple and easy to implement using the ArcGIS raster calculator. They effectively reduce background noise while enhancing contrast features making them suitable for monitoring large-scale changes in peripheral desert areas. However they do not provide classificatory information about the types of changes occurring. Image ratios perform well in monitoring changes in vegetation cover and soil conditions, which is crucial for agricultural areas surrounding Baghdad Governorate although they fall short in accurately identifying land cover shifts. A subsequent comparison of classifications conducted using maximum likelihood classification and merging tools in ArcGIS  enables the identification of start-to-end change trajectories. The findings reveal that urban and industrial areas in Baghdad expanded from approximately 8.5% to 11.8% of the study area between 2004 and 2024  while vegetation cover declined from 16.53% to 9.3% over the same period. The ArcGIS application provides researchers with a flexible and reproducible framework for analyzing changes in Iraqi cities, highlighting the strengths and weaknesses of each methodology employed in semi-arid urban environments.