Accuracy assessment of digital elevation model from aster data using automatic stereocorrelation technique, east Luxor, Egypt

الملخص EN

Digital Elevation Model (DEM) is a raster grid of elevation data that represents features on earth surface.

It is useful for many applications such as mapping, contour derivation and watershed analyses.

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), provides along-track stereo images at 15m spatial resolution with a base-height (B/H) ratio suitable for DEM extraction using automatic stereocorrelation technique.

In the present study the automatic stereocorrelation technique is implemented to derive DEM using the ASTER stereo images (3N & 3B) for east Luxor area, Nile Valley, Upper Egypt, within ENVI v.4.5 environment.

DEM extraction includes two main steps, defining tie points and calculation of epipolar geometry.

24 tie points collected from ASTER stereo images show a good correlation as indicated by yparallax value (0.6331).

15 control points collected from reference topo-map covered the study area as well as the topo-DEM generated from their contours are utilized for accuracy assessment procedure.

Results indicate that the RMSEz values reach 5.4 meters in wadis and low elevation hill (below 300m) whereas in the mountainous areas (above 300m) the RMSEz values scored 27.2 meters.

The present study proved the usefulness of ASTER stereo images for DEM generation with accuracy in Z ranges between 5.4 to 27.2m using automatic stereocorrelation technique.