Extracting Topographic Features From Shuttle Radar Topography Mission (SRTM) Images.

Wei-Wen Feng and Peter Bajcsy

Technical Report NCSA-ALG05-002, July 18, 2005.

This report addresses the problem of extracting topographic features from Shuttle Radar Topography Mission (SRTM) imagery. The features are used for Earth science applications and include slope, curvature, aspect, flow direction, flow accumulation and compound topographic index (CTI). The objective of our work is (1) to support topographic feature extraction similar to the one in ArcGIS, (2) to provide extraction of additional topographic features that are not supported in ArcGIS, (3) to increase statistical robustness of the extracted topographic features and (4) to let Earth science researchers use these algorithms by using the platform independent java code.

We report (1) implementation details of each topographic feature, (2) accuracy comparisons of extracted features by I2K with the features extracted by ArcGIS, (3) differences in the extracted features as a function of statistical sample size, and (4) a summary of supported and unsupported topographic features in I2K and ArcGIS. Our results demonstrate that the results in I2K and ArcGIS software packages are almost identical. Furthermore, availability of additional topographic features and the flexibility of adjusting the feature extraction parameters are provided.