Abstract
Abstract. Height models are a fundamental part of the geo-information required for various applications. The determination of height models by aerial photogrammetry, LiDAR or space images is time-consuming and expensive. For height models with large area coverage, UAVs are not economic. The freely available height models ASTER GDEM-3, SRTM, AW3D30 and TDM90 can meet various requirements.With the exception of ASTER-GDEM-3, which cannot compete with the other, the digital surface models SRTM, AW3D30 and TDM90 are analyzed in detail for accuracy and morphology in 4 test sites using LiDAR reference DTMs. The accuracy figures root mean square error, standard deviation, NMAD and LE90 are compared as well as the accuracy dependence on the terrain inclination. The analysis uses a layer for the open areas, excluding forest and settlement areas. Remaining elements that do not belong to a DTM are filtered. Particular attention is paid to systematic errors. The InSAR height models SRTM and TDM90 have some accuracy and morphological restrictions in mountain and settlement areas. Even so, the direct sensor orientation of TDM90 is better than for the other. Optimal results in terms of accuracy and morphology were achieved with AW3D30 corrected by TDM90 for the local absolute height level. This correction reduces the bias and also the tilt of the height models compared to the reference LiDAR DTM.
Highlights
Digital height models (DHM) are a basic requirement for geographic information systems (GIS) and various other applications
The results can be summarized that the Shuttle Radar Topographic Mission (SRTM), AW3D with 30m point spacing (AW3D30) and TDM90 have a level of accuracy that is satisfactory for various purposes
SRTM is less accurate than the other, the morphological information from SRTM is not that good (Figures 8 – 10) and SRTM is based on radar images of February 2000 – older as the other
Summary
Digital height models (DHM) are a basic requirement for geographic information systems (GIS) and various other applications. DHMs were created with both, but the X-band had the disadvantage of a smaller swath width with large gaps between the covered ones. For this reason the SRTM X-band DHM is not used. The notable large area covering DHM was in 2009 ASTER Global Digital Elevation (ASTER GDEM), based on the stereo models of the Japanese optical satellite TERRA ASTER with 15m ground sampling distance (GSD), later improved to ASTER GDEM2 (Tetsushi et al 2011) and since August 2019 to ASTER GDEM3 (ASTER 2019), where more ASTER scenes are used and a water body tile is included, especially improving the height model at shore lines. AW3D with 30m point spacing (AW3D30) can be downloaded as free, reduced version
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
