GIS Integration of Aster Stereo Imagery for the Support of Watershed Management

In this study, ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) stereo
imagery was analysed in combination with Global Positioning System (GPS) data and field observations,
using Geographical Information Systems (GIS) techniques to examine the potential of satellite
remote sensing to support watershed management. Terrain elevation data were derived for the region
of Heraklion, Crete. The accuracy of the ASTER derived DEM (Digital Elevation Model), was better
than 20 meters (planimetric) and better than 15 meters (elevation). Supervised classification techniques
were applied for land cover production using ASTER multi-spectral imagery and filed observations
at predefined application sites. The determination of training areas required in the supervised
classification scheme was based on these observations. Finally, GIS methods were applied to estimate
watershed characterization parameters for the study area offering the advantages of spatial data handling
capabilities and automatic extraction of thematic information. The drainage pattern, which was
derived, provided a generally representative depiction of the watershed. The output pixel spacing of 15
m of the produced DEM as well as the high spatial resolution of ASTER imagery found to be quite satisfactory
for the watershed characterization of the study area, indicating the high potential of ASTER
imagery to support watershed management.