Modules are divided into 8 categories, each indicated by its prefix. Commands that relate to graphical display such as displaying rasters, vectors, histograms, clearing screen etc. Manipulation of input files such as reading tape header files, extraction of remotely sensed images from tape etc.
Processing includes calculation of cost surfaces, map algebra, buffering etc.
The code for these modules is included in these appendices to provide detailed reference to algorithms and methods described. Modules have been grouped into 4 categories depending on their functionality. DEM analysis modules d.param.scale Allows interactive scale based interrogation of DEM parameters. Can also enforce hydrological connectivity. Output statistics modules r.lags Calculates autocorrelation and texture analysis statistics at a variety of scales and produces a 'lag-diagram' of the results.