Validation of the ASTER Global Digital Elevation Model Version 2 over the conterminous United States

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Abstract

The ASTER Global Digital Elevation Model Version 2 (GDEM v2) was evaluated over the conterminous United States in a manner similar to the validation conducted for the original GDEM Version 1 (v1) in 2009. The absolute vertical accuracy of GDEM v2 was calculated by comparison with more than 18,000 independent reference geodetic ground control points from the National Geodetic Survey. The root mean square error (RMSE) measured for GDEM v2 is 8.68 meters. This compares with the RMSE of 9.34 meters for GDEM v1. Another important descriptor of vertical accuracy is the mean error, or bias, which indicates if a DEM has an overall vertical offset from true ground level. The GDEM v2 mean error of -0.20 meters is a significant improvement over the GDEM v1 mean error of -3.69 meters. The absolute vertical accuracy assessment results, both mean error and RMSE, were segmented by land cover to examine the effects of cover types on measured errors. The GDEM v2 mean errors by land cover class verify that the presence of aboveground features (tree canopies and built structures) cause a positive elevation bias, as would be expected for an imaging system like ASTER. In open ground classes (little or no vegetation with significant aboveground height), GDEM v2 exhibits a negative bias on the order of 1 meter. GDEM v2 was also evaluated by differencing with the Shuttle Radar Topography Mission (SRTM) dataset. In many forested areas, GDEM v2 has elevations that are higher in the canopy than SRTM.

Additional publication details

Publication type Conference Paper
Publication Subtype Conference Paper
Title Validation of the ASTER Global Digital Elevation Model Version 2 over the conterminous United States
DOI 10.5194/isprsarchives-XXXIX-B4-281-2012
Year Published 2012
Language English
Publisher International Society for Photogrammetry and Remote Sensing
Publisher location August 24 - September 3 2012
Contributing office(s) Earth Resources Observation and Science (EROS) Center
Description 6 p.
Larger Work Type Conference Paper
Larger Work Title Imaging a sustainable future, 22nd Congress
First page 281
Last page 286
Conference Title Imaging a sustainable future, 22nd Congress
Conference Location Melbourne, Australia
Conference Date August 24 - September 3 2012
Online Only (Y/N) N
Additional Online Files (Y/N) N