d.thematic.area draws thematic coropleth vector maps based on an attribute column or an expression involving several columns. It takes a number of class breaks (excluding the minimum and maximum values) and a list of colors to apply to the classes (has to be the number of class breaks + 1). The -l flag instructs the module to print legend information (class min | class max | number of observations in class | color) to standard output for futher use in graphical software. When given this flag with the -n flag, the module will only print the legend information without drawing the map. One can used v.class to supply class breaks for d.thematic.area (see example below);


d.thematic.area -l map=communes3 data=pop breaks=111393.250000,222785.500000,334177.750000 colors=255:0:0,0:255:0,0:0:255,0,0,0
The following example uses a calculated attribute (density = pop/area) and v.class to calculate class breaks and feed them directly into d.thematic.area:
d.thematic.area -l map=communes2 data=pop/area breaks=`v.class -g map=communes2 column=pop/area algo=std nbcla=5` colors=0:0:255,50:100:255,255:100:50,255:0:0,156:0:0


v.class d.vect v.univar


Moritz Lennert