Comparison of automated digital elevation model extraction results using along-track ASTER and across-track SPOT stereo images

A digital elevation model (DEM) can be extracted automatically from stereo satellite images. During the past decade, the most common satellite data used to extract DEM was the across-track SPOT. Recently, the addition of along-track ASTER data, which can be downloaded freely, provides another attractive alternative to extract DEM data. This work compares the automated DEM extraction results using an ASTER stereo pair and a SPOT stereo pair over an area of hilly mountains in Drum Mountain, Utah, when compared to a USGS 7.5-min DEM standard product. The result shows that SPOT produces better DEM results in terms of accuracy and details, if the radiometric variations between the images, taken on subsequent satellite revolutions, are small. Otherwise, the ASTER stereo pair is a better choice because of simultaneous along-track acquisition during a single pass. Compared to the USGS 7.5-min DEM, the ASTER and the SPOT extracted DEMs have a standard deviation of 11.6 and 4.6 m, respectively.