Change Detection in Urban Areas using Satellite Data

Satellite data can be regarded as a powerful tool for providing information for urban monitoring that can be used by urban and regional planners in fraction of the cost and time compared to traditional methods (e.g. Aerial photos or field survey). However, most of the methods used in the literature to process such data will need a considerable time and experience. This has limited the application of such technology, since such experience is not always available in urban development sector of the community. The study was conducted over the city of Riyadh, central Saudi Arabia, to test a simple Image Difference (ID) technique for urban change detection. Landsat Thematic Mapper (LTM) data on 21 July, 1987 and 15 September, 1996 and SPOT Panchromatic Linear Array (PLA) data on 2 August, 1996 were acquired over the study area. The change detection using image difference procedure involves: (i) Spatial registration of multi-temporal data sets collected by the different sensors, (ii) Image difference were then used to detect changes in urban areas which enable the detection of changes in brightness values using Pixel by Pixel subtraction of the registered data sets. Three small sub-scenes from the whole study area were generated to evaluate the method in more details. It was found that such technique emphasizes temporal changes and provides an excellent and easy to interpret first level indication of change in urban areas.