Assessment of interpolation methods in producing DEMs from contour lines of 1 : 50000 topographic maps, and their impacts on viewshed analysis

الملخص EN

Digital Elevation Models (DEMs) are regarded as one of the most important data within geo-databases.

There are many interpolation methods of DEMs, whether they interpolate DEMs directly from contour data or by photogrammetric stereoscopic methods.

This paper focuses on evaluation of three methods as implemented within ArcGIS, a GIS system.

They include : TIN, IDW, and Kriging.

The three methods used to interpolate DEMs from contour data which digitized from a 1: 50000 topographic map. Results showed that the interpolated TIN surface, compared to IDW and Kriging surfaces, exhibited a close resemblance to the surface showed by the original digitized contours, as this was chosen as the criterion for the evaluation.

Discussion of the resultant DEMs along with Viewshed analysis, pose important questions and considerations regarding the danger of hasty decisions in singularly identifying one particular interpolation method without taking into consideration data types and analysis nature and requirements.

The study suggests further and similar evaluations, to come up with user guidelines as to which method, along with parameters, is best for particular data, applications, and analysis, so as such guidelines are to be incorporated within GISs.