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The ALOS World 3D – 30 m (AW3D30), ASTER Global DEM Version 2 (GDEM2), and SRTM-30 m are Digital Elevation Models(DEMs) that have been made available to the general public free of charge. An important feature of these DEMs is their unprecedentedhorizontal resolution of 30-m and almost global coverage. The very recent release of these DEMs, particularly AW3D30 and SRTM-30 m, calls for opportunities for the conduct of localized assessment of the DEM’s quality and accuracy to verify their suitability for awide range of applications in hydrology, geomorphology, archaelogy, and many others. In this study, we conducted a vertical accuracyassessment of these DEMs by comparing the elevation of 274 control points scattered over various sites in northeastern Mindanao,Philippines. The elevations of these control points (referred to the Mean Sea Level, MSL) were obtained through 3rd order differentiallevelling using a high precision digital level, and their horizontal positions measured using a global positioning system (GPS) receiver.These control points are representative of five (5) land-cover classes namely brushland (45 points), built-up (32), cultivated areas (97),dense vegetation (74), and grassland (26). Results showed that AW3D30 has the lowest Root Mean Square Error (RMSE) of 5.68 m,followed by SRTM-30 m (RMSE = 8.28 m), and ASTER GDEM2 (RMSE = 11.98 m). While all the three DEMs overestimated the trueground elevations, the mean and standard deviations of the differences in elevations were found to be lower in AW3D30 compared toSRTM-30 m and ASTER GDEM2. The superiority of AW3D30 over the other two DEMS was also found to be consistent even underdifferent landcover types, with AW3D30's RMSEs ranging from 4.29 m (built-up) to 6.75 m (dense vegetation). For SRTM-30 m, theRMSE ranges from 5.91 m (built-up) to 10.42 m (brushland); for ASTER GDEM2, the RMSE ranges from 9.27 m (brushland) to 14.88 m (dense vegetation). The results of the vertical accuracy assessment suggest that the AW3D30 is more accurate than SRTM-30 m andASTER GDEM2, at least for the areas considered in this study. On the other hand, the tendencies of the three DEMs to overestimatetrue ground elevation can be considered an important finding that users of the DEMs in the Philippines should be aware of, and mustbe considered into decisions regarding use of these data products in various applications

the international archives of the photogrammetry, remote sensing and spatial information sciences/international archives of the photogrammetry, remote sensing and spatial information sciences

VERTICAL ACCURACY ASSESSMENT OF 30-M RESOLUTION ALOS, ASTER, AND SRTM GLOBAL DEMS OVER NORTHEASTERN MINDANAO, PHILIPPINES