DEM from stereo Landsat 7 ETM+ data over high relief areas
Landsat 7 ETM+ data provide a new opportunity for users to take advantage of satellite sensor imagery for digital elevation model (DEM) generation, due to its new 15 m resolution panchromatic band sensor, extensive coverage and low cost. Using adjacent-orbit stereo-capability DEM is generated over a high mountainous area of Canada. Each stereo-extracted elevation is compared to 10 m accurate topographic DEM to generate error statistics. The largest errors (172 m with 68% level of confidence) and maximum errors (700 m) are found in areas with clouds, snow, glaciers and shadows because image matching during the correlation process failed. Better 3D visual editing tools than the normal automatic interpolation generally applied should be used in these areas to reconstruct the terrain. Without these factors specific to these challenging mountains (high altitude, shadows, permanent snow covers over 2500 m, glaciers, clouds) an error of 92 m is achieved with a 68% level of confidence.