从GTOPO30到SRTM DEM精度研究——以西藏为例

Study on Accuracy of GTOPO30 and SRTM DEM——A Case Study of Tibet

地形数据对于我们了解全球气候变化、土地构成、大气变化,开展区域水土流失研究非常重要。最近,NASA发布了覆盖全球80%陆地面积的90m分辨率的SRTM DEM数据。在SRTM DEM之前,可以免费获得的精度最高的全球DEM数据是GTOPO30(1km)。由于SRTMDEM数据发布不久,对其实际精度缺乏客观了解,因此有必要对其精度开展研究。以广泛应用的GTOPO30为比较对象,对2种DEM的标称精度、生产方法作了介绍,并以西藏地区为例,利用图形和统计方法,分析、比较了2种DEM数据在1 km分辨率下的精度。总的来说,SRTM DEM精度高于GTOPO30,研究对于SRTM DEM在其它地区的应用具有重要参考价值。

Topographic data are critical to global changes in climate, land formations, atmospheric changes, and research in soil and water loss. Recently, NASA released SRTM DEM at 90-meter resolution covering 80 % of the Earth＇s land surface. Prior to SRTM DEM, GTOPO30 （1 km） was the highest-resolution global DEM. As it is a new product, we have no knowledge of SRTM DEM, and so, it is necessary to assess its accuracy. The article introduces apparent accuracy and production procedure of SRTM DEM in comparison with GT（）PO30. Furthermore, the article analyzes and compares these two DEM datasets at 1 km resolution in Tibet. Results show that SRTM DEM has higher accuracy than GTOPO30. This research can be a good reference for applications in other areas.