Digital Surface Modelling : Applications in Th - E Sugar Industry

A digital terrain model (DTM) is a representation of surface relief encoded in a format which can be analysed by computer. DTMs can be created using any data set which consists of a number of geographi_cal co-ordinates with an elevation or quantity attached to each position. Data which have been represented in this way are topography, meteorological statistics (e.g. rainfall, evaporation and temperature) and soil analysis. Other areas where the use ofDTMs in data analysis could be useful are suggested. The process involved in creating the DTM is discussed. The DTM can then be analysed by interpolation of contours at the desired scale, by interrogation at a specific point using the computer's cursor, or by producing a perspective view three dimensional (3-D) drawing. The Farm Planning department of the South African Sugar Association Experiment Station (SASEX) uses the SURFACE module of their UNIGIS Geographic Information System for producing and analysing DTMs. Analyses in the land use planning environment are carried out with software specifically written for SASEX.