Quality assessment of Digital Elevation Models in comparison with global positioning data of a stream profile in Dera Ismail Khan

Digital elevation models (dems) represent the height of terrain and are widely used in many spatial information related applications. accuracies of dems vary depending upon the requirements of different applications. this paper highlights the height accuracy of dems derived from srtm 90m,aster 30m,hydro1k and google earth technologies against field data of a stream profile collected through global positioning survey. the methods involve collection of variable dems data,developing regression models to find relationship between dems and gps based elevation data,and data quality assessment. the data generated for comparison of the elevation profiles derived from the dems against gps is manipulated with the aid of geographic information system (gis). multiple linear regressions have been used to define the relationship between the dem and the 30 plus gps survey points. the results show a close relationship between the srtm dem and the gps data with mean sum of residual of 0.41m and root mean square error (rmse) of 4m. the study provides insight of different dem technologies available from open sources which can be utilized for detail planning and management of watershed areas of the country in future. © pakistan academy of sciences.