Accuracy evaluation of the SRTM topographic data product over selected sites in Australia and Brunei Darussalam

The paper presents the results of a study on the accuracy of the SRTM band C topography data product (defined in this paper as DTM.C, pronounced as dtm-dot-c), conducted over two selected sites in Australia and Brunei Darussalam. The DTM.C was compared against accurate DTMs developed from 1m (Australian site) and 10m (Brunei site) contours. Land cover data derived from aerial photographs and forestry maps were also used in this study. The discrepancy between DTM.C and DTM allowed the development of an accuracy statement which takes into an account "vegetation" noise caused by the vegetation impenetrability of the band C electromagnetic waves. It was found that the site specific accuracy of the DTM.C could be characterised by a vertical, positive shift equal to 9.8m and 8.3m, and the height error: :ł 11.5m and :ł 18.7m (at 90% confidence level), for the Australian and Brunei sites, respectively. These values agree with the performance requirements for the SRTM data products [4], and could be accepted as a realistic accuracy statement, if DTM. C is used as a surrogate for a DTM over an area of interests.