Evaluation and Assessment of the Impacts of the Spatial Resolution on the Accuracy of the Digital Elevation Model

Fahmy F. F. Asal
Page No. 105-116

Ground surveying methods are main sources for digital elevation data that is usually utilized in the
creation of a Digital Elevation Model (DEM). DEM usually is a main input in many Engineering
and Environmental applications. The quality of the DEM is a vital issue that controls the qualities
of outputs in different applications. Different factors including the data source, the data density,
the sampling method, the spatial resolution and the interpolation scheme control the quality of the
DEM. This research is focused towards investigating the effects of the spatial resolution of the
DEMs generated from ground surveying data on their qualities where digital elevation data has
been collected from a test area of corrugated terrain using ground surveying methods. Qualitative
and quantitative analyses have been applied on DEMs created from digital elevation data with
different resolutions through; visual analysis, statistical analysis, profile analysis and finally
accuracy assessments of the extracted elevations using external checkout points. Visual analysis
has shown texture smoothing due to degradation of the DEM resolution which has been supported
by the statistical analysis results. Also, the analysis using external checkout points has shown
deterioration in the accuracy of the elevations extracted from the DEMs due to degradation of the
DEM resolution.
Keywords : DEM/DSM/DTM; DEM resolution; DEM grid cell size; Visual analysis; Elevation
accuracy; Spatial analysis..