Development of a Computer Programfor Calculating Topographic Index with GIS.
Joon-Hak Lee and Woo-Kyun Lee

 

ABSTRACT : In this study, a computer program for calculating topographic in ... ex based on Digital Elevation Model(DEM) and multiple flow direction method was developed. The program was design in the way that it's input and output file format 1s compatible to ASCII format of ESRI's GRID module for GIS, It was made with Visual Basic and can be used under MSWindows on personal computer. Two kinds of topography was used for testing the program. The ideal topographic model of corn form was tested to validate the multiple flow direction method used for calculating topographic index in the program. As a result , multiple flow method shows better performance than single flow method for calculating topographic index. The test of the program with real topographic data showed that the program can be well applicable to the real topographic site. Topographic index or wetness index, which implies the concentration of water flow in topographic site with various aspect, height and slope, is closely related to the spatial distribution of soil moisture. Accordingly the program for calculating topographic index can apply to studies on classification of forest site type with GIS.

Key words : topographic index. wetness index. multiple flow method. DEM. GIS. forest site type