ASSESSMENT OF 1" SRTM DATA QUALITY IN CHINA TAKING LOESS HILLY AREA AS AN EXAMPLE

The Shuttle Radar Topography Mission (SRTM) C-band is an important elevation data at regional scale. The 1" SRTM elevation data has been released in 2014 over China. A detailed evaluation of 1" SRTM data in China is still lacking. In this paper, the 1" SRTM data quality is assessed by comparing with the 25m DEM data based on 1: 50000 scale topographic maps taking loess hilly area in China as an example. And the 2.5m DEM data based on 1: 10000 scale topographic maps was chosen as reference data. The result showed slope based on 1" SRTM data reduced and slope length increased according to 1: 10000 scale topo maps. The terrain features such as contours lines, stream lines and ridge lines showed some difference between the three DEMs. The difference of terrain parameters and terrain features were larger in 1" SRTM data than in 25m DEM data referenced to 1: 10000 scale topographic maps which indicated 25m DEM data based on 1: 50000 scale topographic maps may have better data quality than 1" SRTM data. Some efforts still needed to improve the data utility of 1" SRTM data at regional scale.