WorldDEM
WorldDEM (DEM for English D igital E levation M easurements to German "digital height measurements") is a global digital elevation model . It covers the entire land mass of the earth and has been available since 2016.
Data acquisition
The WorldDEM database was captured by the German radar satellites TerraSAR-X and TanDEM-X . The mission was implemented as part of a public-private partnership between the German Aerospace Center ( DLR ) and EADS Astrium .
Radar sensors record data very reliably because they work independently of weather and light conditions. The most important advantage of satellite-based data acquisition is the acquisition of a global offset-free elevation model, free from inhomogeneities at regional or national borders that can arise from different measurement methods and time-staggered campaigns. TerraSAR-X and TanDEM-X fly at a distance of at times only 200 m and form an accurate radar interferometer in space. The data was collected in bi-static mode: one satellite sends the radar signal to the ground, and both satellites receive the signal reflected from the ground. With the help of SAR interferometry ( InSAR ) the phase difference of the received signals was evaluated and the altitude information derived.
Data acquisition for WorldDEM began in December 2010 and ended after about three years. The entire land mass of the earth was surveyed at least twice (difficult areas were covered up to four times) to ensure the final consistent quality and accuracy.
Dissolution and License
WorldDEM has a resolution of 12 meters with a relative horizontal accuracy of 2 meters. This allows objects such as houses or individual trees to be clearly displayed. WorldDEM has been publicly funded but is not freely licensed. License fees are due for use depending on the size and resolution of the requested area.
See also
- ASTER height profile
- SRTM data - free DEM from NASA and DLR with 30 meter resolution worldwide
- ALOS - free DEM from JAXA with 30 meter resolution worldwide
Web links
- WorldDEM at Airbus Defense and Space
- TerraSAR-X at Airbus Defense and Space
- TanDEM-X at DLR