Comparison of DEM Accuracies Generated by Various Methods

Presently, various different methods are being used for digital elevation model (DEM) generation. DEMs can be generated from topographic maps obtained with terrestrial measurements, photogrammetric flight data or remote sensing technologies. And also a question can be asked that which method is better than others that´s why these DEM generation techniques have been analysed and the accuracies of DEMs have been compared in this study. For Zonguldak test field, three types of DEMs have been used. First DEM has been produced by digitized contour lines of 1:25000 scale topographic maps, second one has been produced by photogrammetric flight project data had been made by Zonguldak Municipality in 2005 and last one has been derived from Shuttle Radar Topography Mission (SRTM) X-band data which has used single-pass interferometric synthetic aperture radar (InSAR) technique for DEM generation. In the study, all these DEMs have been compared one by one based on selected reference. The DEM produced with Photogrammetric method has approximately 5.5 m better accuracy for open and flat, 6.5 m better accuracy for forest areas against the DEM generated from 1:25000 scale topographic maps. SRTM X-band DEM is 4 m less accurate for open, 4.5 m less accurate for forest areas against the DEM produced with photogrammetric method and 9.5 m less accurate for open, 11 m less accurate for forest areas against the DEM generated from 1:25000 scale topographic maps. And at the result, it has been clearly seen that the DEM produced by photogrammetric flight project in 2005 has better accuracy than the others.