3-D expression of relief in Landsat Thematic Mapper and SPOT P images

Abstract

Perceptual problems of viewing topography on geoimages are caused by illumination from the southeast during data collection. This problem affects the majority of satellite images. The aim of this work is to obtain a stereoscopic effect of shaded relief in such images. Techniques available in commercial digital processing programs are used in the absence of a digital elevation model. The images used are taken by the Landsat TM and SPOT P satellites; the software used was the EASI-PACE and ACE programs (Canadian PCI Geomatics Group). The pseudoscopic effect is solved by using the first principal component obtained in a principle components analysis of the three channels, resulting from the weighted merging of the Landsat and SPOT data. The map obtained provides the observer a view with shaded relief.