Characteristics of 3" SRTM Errors in China

The 3" SRTM elevation error in China were methodically evaluated by using sample survey at more than five hundred thousand sites. The characteristics of SRTM errors was identified according to the landscape attributes. The results showed that SRTM error is closely related to different topography and land cover types. The error changes from positive to negative with its absolute value getting bigger with increasing slope; Positive error concentrate in north facing aspect, while negative error in southwest facing aspect; The error increases with increasing vegetation cover fraction; In the regions of glacier, desert and wetland, the mean errors are negative, while in building areas the mean error is positive. Among different factors, slope plays the pivotal role affecting SRTM errors. Additionally, SRTM data has significant abnormity in some areas such as desert and steep mountain, and arise stripes in flat areas.