Abstract
Digital image processing methods were applied on Landsat-8 data to differentiate different natural land covers and urban areas in Jizan, Red Sea Coast, Saudi Arabia. The computer-aided works were combined with field investigation to confirm the achieved results. The false-color image with bands 5, 4, and 3 in RGB, respectively, was found useful in delineating between sabkha and non-sabkha areas. The sabkha areas are characterized by hues of light brown color, and the non-sabkha areas have hues of light grey to light bluish color. A false-color image with bands 5, 6, and 4 clearly differentiates between mangroves in hues of red color and other vegetation in hues of orange color. The principal component analysis (PCA) image clearly shows the wadi drainage and estuary in several shades of green color; the coastal sabkha areas have hues of blue, which range from light blue (denoting dry sabkha) to dark blue (denoting wet sabkha), and sand dunes are shown in fuchsia color. The results of this study identify features such as urban populated areas, land vegetation, moisture intensity in the sediments, shallow and deep waters, reef islands, sabkha and non-sabkha areas, salt dome, shores, tidal flats, wadi drainage, mangrove habitat, the width of shallow seawater, and land-seawater contacts. Several maps are produced in this study showing the distribution of the abovementioned features. These maps will be useful as a base reference for further studies by geologists, engineering geologists, hydrogeologists, and governmental decision leaders.