للكاتبين Fahmy F. Asal*, and Raaed Hassouna*
Faculty of Engineering, Menoufia University, Egypt
ABSTRACT:
Due to increasing availability of digital elevation data and rapid advances in computer
technology the utilization of Digital Elevation Models (DEM) in Surveying and Mapping
have greatly expanded in the last several years (Lo and Yeung, 2004). Ground surveying
measurements either using conventional techniques or using RTK GPS methods, digital
photogrammetry and the newly established airborne laser scanning which applies LiDAR
technology are main sources for the measurements used in the creation of DEMs. Most of
mapping techniques provide discrete measurements on a point support which are to be
subjected to interpolation operation for the creation of DEM. GIS and image processing
systems such as ArcView GIS and ERDAS IMMAGINE provide means for interpolating
DEM basing on different interpolation approaches such as Inverse Distance Weighting (IDW)
method, spline approach and kriging techniques. Different interpolation methods have to be
expected to provide DEMs of varying qualities. This research applies accuracy assessment
analysis and quality investigations on DEMs obtained from IDW and spline interpolators in
order to assess how efficient each of these methods in creating DEM that can be a good
representation to the real world. The analysis has shown that IDW method provides better
quality DEM than the DEM obtained from the spline approach which smoothes the terrain
and provides noise DEM of lower accuracy in elevation determination than the IDW DEM.