ACCURACY ASSESSMENT OF DIGITAL
ELEVATION MODEL (DEM) DATA
OBTAINED FROM ASTER SATELLITE IN
FLAT LAND

January, 2016

ABSTRACT
It is important to investigate the accuracy of Digital Elevation Models (DEMs)
because of their decisive impact on all engineering and scientific applications;
Photogrammetry, traditional surveying, remote sensing systems and satellite whole
DEMs output methods. In this paper include the Global Digital Elevation Model
(GDEM) data produced by the ASTER satellite Advanced Space borne Thermal
Emission and Reflection Radiometer (Band near-infrared wavelength region from
0.78 to 0.86 𝜇𝑚), where tested and evaluation DEM data for an area of 100 square
kilometers in Al-Shtra city in Dhi-Qar Governorate about 400 km southern of
Baghdad capital . The technique which are used to evaluate the DEM accuracy was
twofold: first method was to use statistical methods and the second method is to take
advantage of applied linear transformation equation to detect the gap between ZDEM
and Z-Global Navigation Satellite System (GNSS) which is represents reality.
The result of a root means square error (RMSE) is ∓5.087m, where it was calculated
based on the observed data in the field using GNSS. And standard deviation error
(SDT err) was ∓5.088 m, while after applied linear transformation equation on the
ASTER DEM data the RMSE reduction to about 80%, which indicates that there are
too much bias between the Z-DEM and Z-GNSS.