document: Comparison of automated digital elevation model extraction results using along-track ASTER and across-track SPOT stereo images A digital elevation model -LRB- DEM -RRB- 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
doc_bio_tags: O O B I I I I O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O
extractive_keyphrases: automated digital elevation model extraction stereo satellite images aster stereo pair radiometric variations
abstractive_keyphrases: along-track aster data across-track spot stereo images spot stereo image pair simultaneous along-track acquisition