An Adaptive Terrain-Dependent Method for SRTM DEM Correction Over Mountainous Areas

Abstract

This paper presents a terrain-related method to simultaneously correct the global error trends and local linear/nonlinear terrain-related errors of the Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM), which have not been focused in most of the previous methods. To meet this goal, an adaptive strategy for modelling the SRTM DEM errors is first proposed, especially over mountainous areas, based on the Bayesian information criterion. Then, the M-estimator, instead of the ordinary least squares' solver, is utilized to estimate the model parameters of the constructed model to improve the estimation robustness. The proposed method was tested over the Zhangjiajie areas of China, where the ground surface terrain varies from plains to steep mountains. The results show that the errors of the SRTM DEM over the region of interest decrease from 10.1 m to approximately 8.1 m after correction with the proposed method, indicating an improvement of approximately 20%. In addition, compared with two existing and common methods that can correct the global error trends and local linear terrain-related errors of the SRTM DEM, the accuracy of the corrected SRTM DEM improves by approximately 29% and 27.9% over mountainous areas with slopes larger than 20° when the proposed method is used. Moreover, the proposed method will be beneficial to the correction of other airborne or spaceborne DEM products, especially over mountainous areas.

Evaluation of the Vertical Accuracy of Open Global DEMs over Steep Terrain Regions Using ICESat Data: A Case Study over Hunan Province, China

“…As Figure 4 shows, the DEM errors of all datasets decrease significantly with the increasing slope, suggesting that the terrain slope has stronger effect on the DEM errors of both InSAR and optical photogrammetry technology. Furthermore, this result provides a possibility for us to correct DEM errors related to ground slope, as demonstrated in [ 53 ].…”

“…Results furthermore show that DEM errors significantly increased with increasing slope value above 6°, which can be used to corrected the systematic errors caused by terrain slope angles [ 53 ]. However, no relationship was found between the vertical error and terrain aspect, whereas the DEM vertical accuracy significantly decreases as the land cover ranges from non-vegetated to vegetated.…”

Comments on “An Adaptive Terrain-Dependent Method for SRTM DEM Correction Over Mountainous Areas”

“…Intuitively, the discretization error can be reduced using a smaller pixel size. The variance of a discretization error can be estimated using (1) [2]:…”

“…Zhou et al used a large set of GNSS stations as a reference [1]. Some of the GNSS points belonged to the Continuously Operating Reference Stations (CORS) network.…”

“…In an IEEE Access article [1], Zhou et al presented a method for modeling vertical errors of the Shuttle Radar Topography Mission (SRTM) digital elevation data product in order to "correct" it or to improve the product's accuracy. While investigating the properties of a digital elevation model (DEM), including determining its vertical accuracy, is a good research topic, a declared intention to correct a global DEM based on circumstantial evidence appears incorrect and inappropriate.…”