Abstract
The recently released TanDEM-X intermediate digital elevation model (IDEM) product by the German Aerospace Center (DLR) provides elevation models at 12-m spatial resolution and above. It was derived from bistatic synthetic aperture radar (SAR) interferometry using the two TerraSAR-X satellites flying in close constellation. The aim of this study was to validate the vertical accuracy of the IDEM data at study sites in the Kruger National Park, South Africa. Two validation locations are presented: a dried up former reservoir (Nhlanganzwani Dam) characterized by bare soil and grassland and the peninsula between the Sabie and Sand Rivers near Skukuza characterized by dense woody cover. The results show that the IDEM elevation data are affected by residual vegetation canopy height and landform features smaller than the IDEM resolution cell. The scattering phase centers are located in the canopy but at a lower height than the location of the LiDAR first return signal. When only LiDAR ground hits or differential GNSS ground survey points are used for comparison, the IDEM data have an rmse < 1 m and a small bias of less than 0.25 m in moderate terrain.
Highlights
D IGITAL elevation models (DEMs) represent fundamental data for a range of applications including Earth surface process studies in the field of ecology, geology, geomorphology, and hydrology, among others
The past two decades have witnessed a continuous growth in the use of satellite-based data, either based on synthetic aperture radar interferometry like the suite of SRTM SIR-C products or optical images like the ASTER-GDEM, for the production of DEMs
The Kruger National Park (KNP), South Africa, with 20 000 km2 is Africa’s largest national park. It is covered by a diverse range of savanna vegetation communities with varying density of woody vegetation coexisting with grasses and forbs
Summary
D IGITAL elevation models (DEMs) represent fundamental data for a range of applications including Earth surface process studies in the field of ecology, geology, geomorphology, and hydrology, among others. The past two decades have witnessed a continuous growth in the use of satellite-based data, either based on synthetic aperture radar interferometry like the suite of SRTM SIR-C products or optical images like the ASTER-GDEM, for the production of DEMs. In 2014, the German Aerospace Center (DLR) released the first version of its intermediate DEM (IDEM) from the TanDEM-X satellite mission. In 2014, the German Aerospace Center (DLR) released the first version of its intermediate DEM (IDEM) from the TanDEM-X satellite mission This constellation of two satellites flying in a close orbit formation acquires radar images of the land surface at high spatial resolution, i.e., the stripmap mode [1]. DEM data products are being developed at 12-, 30-, and 90-m resolution
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
