Digital Relief Models
Information about the terrain is necessary in the implementation of various geoinformation projects, as well as in the orthotransformation of remote sensing data (remote sensing). The most important sources of such information are digital elevation models (DEM) and terrain (DTM). DEMs are accurate data on the height of the earth’s surface, including buildings, vegetation and other high-altitude objects, and the DTMs contain information on the height directly above the earth’s surface. Global DEM and DTM are based mainly on stereoscopic optical and interferometric radar space imagery.
Briefly about the main thing
1. GEO Elevation Services – The Airbus Defense and Space product line under the general name GEO Elevation Services, related to digital elevation and terrain models, includes WorldDEM, Elevation1, Elevation4, Elevation8, Elevation10 and Elevation30.
2.SRTM 2.SRTM – International mission to obtain data from the digital terrain model (DEM) of the Earth. A radar interferometric survey of the globe’s surface was conducted aboard the Shuttle reusable spacecraft. As a result of the SIR-C (SRTM C-band) survey, a digital terrain model of almost 80% of the Earth’s surface was created. SRTM data is available in several versions: preliminary (version 1, 2003) and final (version 2, February 2005). The final version has undergone additional processing, selection of shorelines and water bodies, filtering of erroneous values. The data is distributed in several versions. More accurate data (SRTM1), cell size 30×30 is available in the US, on the rest of the earth’s surface only data with a cell size of 90×90 m (SRTM3) are available. All data is publicly available and available for download. In 2011, according to the X-SAR sensor, the German Aerospace Agency (DLR) created the SRTM X-band with a cell size for the entire coverage of 30×30 m.
A Sample product WorldDem with a resolution of 12 m: