SRTM (Shuttle Radar Topography Mission), jointly measured by NASA and the National Surveying and Mapping Administration (NIMA). On February 11, 2000, the USS Endeavour, launched by the United States, was equipped with an SRTM system and conducted a total of 222 hours and 23 minutes of data collection work to obtain radar image data covering a total area of over 119 million square kilometers between 60 degrees north and 60 degrees south latitude, covering over 80% of the Earth's land surface. The data volume of radar images obtained by the SRTM system is approximately 9.8 trillion bytes. After more than two years of data processing, a digital terrain elevation model (DEM), now known as the SRTM terrain product data, has been developed. This data product has been publicly released since 2003 and has undergone multiple revisions. The current revised version of the data is V4.1. This version of SRTM terrain data was obtained by CIAT (International Tropical Agriculture Center) using a new interpolation algorithm, which better fills the data gap of SRTM 90. The interpolation algorithm comes from Reuters et al. (2007)

 Gansu Province DEM data 90 meters uses SRTMDEM 90M resolution DEM data as the data source for image processing such as data stitching and resampling, and then uses Gansu Province's regional boundary clipping to generate DEM data products with a spatial resolution of 90 meters.