ACCURACY INVESTIGATIONS OF DIGITAL TERRAIN MODELS (DTMS) CREATED FROM DIFFERENT DATA SOURCES

Abstract

Surface modeling is a general term, which is used to describe the process of representing a physical or artificially created surface by means of a mathematical expression. Terrain modeling is one particular category of surface modeling which deals with the specific problems of representing the surface of the earth.

The Digital Terrain Model (DTM) 1s simply a statistical representation of the continuous surfuce ofthe ground by a large number of selected points with known X, Y, Z coordinates in an arbitrary coordinate field system.

In this context, a grid-based digital terrain models were derived from both digitized contour lines and digital image matching techniques. The first was obtained by interpolating with a high quality algorithm scanned and vectored contours of existing topographic sheets. The second was extracted from scanned aerial photographs using a soft copy Photogrammertic system (Helava).

By comparing each DTM with a third terrain model generated from traditional ground surveying technique, as three different data sources. Then investigate the accuracy of each DTM generated from each data source.

The obtained results showed that, the DTM generated from the ground surveying data is the best one, followed by that generated from Photogrammertic data, finally, the DTM generated from the contour maps is coming at the end.