Comparison of TanDEM-X DEM with LiDAR Data for Accuracy Assessment in a Coastal Urban Area

Abstract

The TanDEM-X (TDX) mission launched by the German Aerospace Center delivers unprecedented global coverage of a high-quality digital elevation model (DEM) with a pixel spacing of 12 m. To examine the relationships of terrain, vegetation, and building elevations with hydrologic, geologic, geomorphologic, or ecologic factors, quantification of TDX DEM errors at a local scale is necessary. We estimated the errors of TDX data for open ground, forested, and built areas in a coastal urban environment by comparing the TDX DEM with LiDAR data for the same areas, using a series of error measures including root mean square error (RMSE) and absolute deviation at the 90% quantile (LE90). RMSE and LE90 values were 0.49 m and 0.79 m, respectively, for open ground. These values, which are much lower than the 10 m LE90 specified for the TDX DEM, highlight the promise of TDX DEM data for mapping hydrologic and geomorphic features in coastal areas. The RMSE/LE90 values for mangrove forest, tropical hardwood hammock forest, pine forest, dense residential, sparse residential, and downtown areas were 1.15/1.75, 2.28/3.37, 3.16/5.00, 1.89/2.90, 2.62/4.29 and 35.70/51.67 m, respectively. Regression analysis indicated that variation in canopy height of densely forested mangrove and hardwood hammock was well represented by the TDX DEM. Thus, TDX DEM data can be used to estimate tree height in densely vegetated forest on nearly flat topography next to the shoreline. TDX DEM errors for pine forest and residential areas were larger because of multiple reflection and shadow effects. Furthermore, the TDX DEM failed to capture the many high-rise buildings in downtown, resulting in the lowest accuracy among the different land cover types. Therefore, caution should be exercised in using TDX DEM data to reconstruct building models in a highly developed metropolitan area with many tall buildings separated by narrow open spaces.

Reconstruction and Evaluation of DEMs From Bistatic Tandem-X SAR in Mountainous and Coastal Areas of China

“…In this study, the overall absolute vertical accuracy of the high-resolution TanDEM-X DEM evaluated with accurate GPS measurements is 1.7m, which is largely consistent with the DLR official validation report [22,23] as well as most of the independent results in other areas outside of China [2,6,8,19,24,25,29,59]. As a DSM, the TanDEM-X DEM does not represent the bare earth surface in those areas with vegetation and man-made objects, e.g.…”

DEM Generation from Fixed-Wing UAV Imaging and LiDAR-Derived Ground Control Points for Flood Estimations

“…Based on the above metadata, we assume that the LiDAR dataset falls within the vertical accuracy of ASPRS 20 cm class [42] and quality level QL3 (≤ 20 cm RMSE), according to USGS specifications [52]. The expected accuracy of modern LiDAR (e.g., vertical < 10 cm RMSE, see Zhang et al [53]), should fall within the high accuracy classes by USGS and ASPRS standards. The description of the orthometric height correction of the 1 m TIN-based LiDAR DEM (and DSM) are found in Escobar et al [54].…”

A Relief Dependent Evaluation of Digital Elevation Models on Different Scales for Northern Chile

“…For the SRTM1 DEM the results show an average error of 3-4 m in flat landscapes up to 7-8 m in mountainous areas. Additionally, the accuracy of the newer ALOS World 3D [45] and the TanDEM-X World DEM ™ [46][47][48] was assessed by comparing them with various reference datasets. Several studies directly compared the performance of different global elevation models in various geographical settings.…”