A geomorphology-based approach for digital elevation model fusion – case study in Danang city, Vietnam
Global digital elevation models (DEM) are considered a source of vital spatial information and find wide use in several applications. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global DEM (GDEM) and Shuttle Radar Topographic Mission (SRTM) DEM offer almost global cove...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-07-01
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| Series: | Earth Surface Dynamics |
| Online Access: | http://www.earth-surf-dynam.net/2/403/2014/esurf-2-403-2014.pdf |
| Summary: | Global digital elevation models (DEM) are considered a source of vital spatial
information and find wide use in several applications. The Advanced Spaceborne
Thermal Emission and Reflection Radiometer (ASTER) Global DEM (GDEM) and
Shuttle Radar Topographic Mission (SRTM) DEM offer almost global coverage
and provide elevation data for geospatial analysis. However, GDEM and SRTM
still contain some height errors that affect the quality of elevation data
significantly. This study aims to examine methods to improve the resolution
as well as accuracy of available free DEMs by data fusion techniques and
evaluating the results with a high-quality reference DEM. The DEM fusion
method is based on the accuracy assessment of each global DEM and
geomorphological characteristics of the study area. Land cover units were
also considered to correct the elevation of GDEM and SRTM with respect to
the bare-earth surface. The weighted averaging method was used to fuse the input
DEMs based on a landform classification map. According to the landform types,
the different weights were used for GDEM and SRTM. Finally, a denoising
algorithm (Sun et al., 2007) was applied to filter the output-fused DEM. This
fused DEM shows excellent correlation to the reference DEM, having
a correlation coefficient <i>R</i><sup>2</sup> = 0.9986, and the accuracy was also
improved from a root mean square error (RMSE) of 14.9 m in GDEM and 14.8 m in SRTM
to 11.6 m in the fused DEM. The results of terrain-related parameters extracted
from this fused DEM such as slope, curvature, terrain roughness index and
normal vector of topographic surface are also very comparable to reference data. |
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| ISSN: | 2196-6311 2196-632X |