Comparison of ASTER GDEM3, SRTM3, NASADEM, TanDEM-X90, AW3D30, and ALOS PALSAR Data with TanDEM-X12: a Case Study of Tagragra of Akka Inlier, Moroccan Anti-Atlas

Digital elevation models (DEMs) provide valuable information for many scientific applications that rely on elevation and digital terrain modeling. In recent years, remote sensing DEMs have been widely used due to their enhanced spatial coverage and spectral characteristics. However, the accuracy of these data must be discussed because this considerably influences the reliability of the extracted information. In the present work, we performed an accuracy assessment of the latest versions of six freely available global DEMs, namely, ASTER GDEM3, SRTM3, NASADEM, AW3D30 (spatial resolution of 30 m), TanDEM-X90 (90 m), and ALOS PALSAR (12.5 m), while comparing them with a high-accuracy TanDEM-X12 (12 m) as reference DEM. This evaluation was carried out by comparing the descriptive statistics of elevation, error differences, R2 correlation coefficient, DEMs of difference (DoDs), and slope analysis. Overall, the obtained results indicated that the highest accuracy is reached by ALOS PALSAR, NASADEM, and SRTM3. Despite its high spatial resolution, ALOS PALSAR did not differ too much from SRTM3 and NASADEM in terms of accuracy. In the horizontal assessment, TanDEM-X90 was better than AW3D30 and ASTER GDEM3 while showing very close RMSE values to the three best DEMs, even with its coarser spatial resolution. AW3D30 gave moderate errors in all results, whereas the most significant errors were obtained from ASTER GDEM3. We concluded that radar DEMs gave the most reliable information compared to optical DEMs for our study area context.