| Assessment of Extracting Topographic Surface Features Using Different Open Sources DEMs |
| Paper ID : 1008-ICRSSSA-FULL (R1) |
| Authors |
|
Ateaya Bekheet Azeez1, Ashraf Mohamed Ahmed Sharawy2, Mohamed Badawy *3, Mohamed Abd Elaziz Ahmed4 1Head of land survey department and lidar lab manager, NARSS. 2Arial Photography Aviation Department, NARSS 3GIS Specialist, NARSS 4PhD Lecturer of Physical Geography & GIS, Helwan University |
| Abstract |
| Digital Elevation Models (DEMs) represents the basis on which geographical studies, in general, and geomorphological and hydrological studies, in particular, depend. Generally, many open-source DEMs are currently in use, and significant differences have been noted between their results. During the current research, high-accurate DEM was created using modern geomatics techniques (i.e. GNSS). Then, a comparison was carried out between a total of common 100 points, which were carefully chosen and measured in both high-accurate digital models, and open source DEMs extracted from satellite images (i.e. ASTER DEM - SRTM1 - Alos DEM 12.5 - Alos DEM 30), where a number of statistical indicators were applied to these models. Output evaluation results indicate that there were large differences in the accuracy of the height discrepancies, however, the open-source model namely: SRTM1 gives the highest accuracy and additionally, is considered the closest accurate height model to the high-accurate DEM created using GNSS. Accordingly, open-source SRTM1 DEM was enhanced using high accurate DEM. Finally, an analysis of surface topography for the study area (New Cairo City) was carried out using two DEMs (SRTM1 – Modified SRTM1), which resulted in a significant difference in the output parameters. In the of each the two models. |
| Keywords |
| Digital Elevation models – Geomatics – Topography – GIS – GNSS |
| Status: Accepted (Oral Presentation) |
