A Comparative Study of Australian Cartometric and Photogrammetric Digital Elevation Model Accuracy

Abstract

This paper explores the accuracy of Digital Elevation Models (DEMs), with particular reference to Australian published DEMs. Direct comparisons were made between cartometric and automatically measured photogrammetric DEMs at various grid spacings with an accurate and dense set of ground truth data. The cartometric DEMs were found to be more accurate than the photogrammetric DEMs for the small study site in this paper, with RMS errors in elevation of approximately 3.5 m and 4.5 m, respectively, and maximum absolute errors in elevation of approximately 12 m and 28 m, respectively. An important factor for environmental prediction studies is slope, and RMS errors in slope were approximately 6 percent and 20 percent for the cartometric and photogrammetric DEMs, respectively, with maximum absolute errors in slope of approximately 75 percent and 290 percent, respectively. However, use of suitable postprocessing such as filtering may reduce the errors in photogrammetric DEMs to at least the same magnitude as cartometric DEMs. The cartometric DEMs were found to satisfy the USGS specifications for Level 2 data.