AN ACCURACY STUDY OF A DEM GENERATED FROM SPOT 
Jude Huang and Andris Zusmanis 
ERDAS, Inc. | 
2801 Buford Highway, Suite 300 | 
Atlanta, Georgia 30329, USA 
Zong-Guo Xia 
Department of Geography 
714 Swift Hall 
University of Cincinnati 
Cincinnati, Ohio 45221-0131, USA 
Abstract 
| KEY 
This study analyzes the accuracy of a digital elevation model (DEM) that was created from SPOT stereo pair images. | 
The accuracy of the DEM will be analyzed thoroughly from all aspects. First as a raster image, the overall statistics of | ABS 
the elevation data will be compared with USGS 1:24,000 DEM data. À difference image will also be generated for 
point to point comparison. Secondly, the elevation of dozens of ground control points and triangulation check points In 
used in image matching and DEM generation will be compared with their elevation values from 1:24,000 USGS quad wil 
maps. Thirdly, about a hundred points will be randomly picked from the entire study area and their elevation values mod 
will be compared with the quad maps as well as the DEM from USGS. Fourthly, the geographical distribution of error | Frc 
residual and their correlation with slopes, shadows, surrounding landscape and other factors will be studied. Finally, | fou 
the relationship between image resolution and DEM reliability will be discussed. We chose our study area to be Irish fol 
Canyon, Colorado, and we use the ERDAS Digital Ortho Module to extract elevation data from SPOT stereo pair im- | 
ages. | 
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