THE RASTER GIS DESIGN-MODEL - A PROFILE OF ERDAS

ERDAS is an Image Processing (IP) and Geographical information System (GIS) based on the raster spatial data model. It supports a wide variety of typical GIS data capture, checking, manipulation, analysis, and display functions. Although a number of other functions could be implemented, the data model is not conducive to the implementation of some GIS functions, such as critical path analysis, coordinate geometry, cartographic display, and attribute database linkage. It is concluded that the raster model has a number of advantages over the vector model. These include simplicity, low cost and speed, together with suitability for proximity analysis, modeling and simulation, intervisibility, and boolean operations.