TITLE:
Comparison and Validation of the Recent Freely Available DEMs over Parts of the Earth’s Lowest Elevation Area: Dead Sea, Jordan
AUTHORS:
A’kif Al-Fugara
KEYWORDS:
ASTER-GDEM ver.2, SRTM ver.4.1, Aerial Photos, Vertical Accuracy, Dead Sea
JOURNAL NAME:
International Journal of Geosciences,
Vol.6 No.11,
November
23,
2015
ABSTRACT: The present research study
assesses the accuracy of two recent freely available ASTER-GDEM ver.2, SRTM
ver.4.1 digital elevation models for parts of the lowest area on the earth on
the shores of the Dead Sea, the site located over areas with high variation in
topography within the “humratessahan” watershed, where the elevation varies
between 700 m above sea level in the north east of the watershed to 210 meter
below sea level. The reference elevation data used in this study are
topographical points extracted from existing digital vector topographical map
published by Royal Jordanian Geographical Center (RJGC). However, the contour
lines do not cover the whole area especially in the flat areas where elevation
is less than the contour line interval. Therefore, the second reference data
created with photogrammetric techniques from stereoscopic pairs of aerial
photos had been used for the surface to surface comparison and elevation
profiles assessment purpose. It is demonstrated that the vertical accuracy of
ASTER-GDEM ver.2 is 22.223 m (Root Mean Square Error (RMSE)) against reference
elevation data, while the SRTM ver.4.1 has an RMSE of 15.858 m; the statistics
results indicate that the theoretical accuracy is achievable and meets the
expected accuracy specification. Furthermore, as for its unprecedented detail,
it is believed that the photogrammetric derived DEM offers an alternative in
accessibility to high-quality elevation data with vertical accuracy of 0.78 m
(Root Mean Square Error (RMSE)).