Radar satellite images could be used to produce digital elevation model (DEM) of certain areas by processing a couple of images, covering the same area, obtained at two different angles. In this study, the DEM generated from the Canadian RADARSAT stereoscopic data for a north western area of the Gulf of Suez, Egypt, is compared to the DEM generated from the topographic contour maps, scale 1:50,000. An evaluation and assessment of the results were conducted. The study shows that the DEM derived from RADARSAT data has a high precision as compared to the one generated from the topographic maps. It is also accurate enough to provide information where other sources of digital elevation are not available.
A variety of techniques exist for change detection of multitemporal remotely sensed satellite data. The Intensity- Hue-Saturation (IHS) color space is very useful for image processing because it separates the color information in ways that correspond to the human visual system's response. In this study, a novel approach, emphasizing the use of the hue component of the IHS transformations of Landsat data, is proposed and examined for multitemporal change detection. Two Landsat Thematic Mapper (TM) scenes acquired on 1987 and 1997 covering the western part of El-Fayoum area and El- Rayan lakes in Egypt have been processed (geometrically corrected and radiometrically balanced) and transformed to the IHS space. The results of using the hue component in detecting the changes are very promising. A number of changed areas including water and agriculture land were successfully detected. The used color theme print, which display the spatial pattern of change in map form, was of great significance in interpreting the environmental changes and the statistical estimation of these changes has been carried out as well.