DESCRIPTION transforms GRASS vector map layers into GRASS raster map layer format. Optionally, attributes can be converted into raster category labels.

NOTES will only affect data in areas lying inside the boundaries of the current geographic region. Before running, the user should therefore ensure that the current geographic region is correctly set and that the region resolution is at the desired level.

Either the column parameter or the value parameter must be specified. The use option may be specified alone when using the dir option.

use options are:

The column parameter uses an existing column from the vector map database table as the category value in the output raster map. Existing table columns can be shown by using db.describe.

An empty raster map layer will be created if the vector map layer has not been assigned category/attribute labels (e.g., through use of v.category option=add).


Flow directions are given in degrees counterclockwise from east.

Raster category labels are supported for all of use= except use=z.


1. Convert a vector map and use column SPEED from attribute table
db.describe -c table=vect_map

Column 1: CAT
Column 2: SPEED
Column 3: WIDTH in=vect_map out=raster_map col=SPEED

2. Calculate stream directions from a river vector map (Spearfish) in=streams out=streamsdir use=dir

3. Convert a vector polygon map to raster including descriptive labels (Spearfish) in=fields out=myfields use=attr col=cat labelcol=label
r.category myfields


db.describe, v.category


Original code: Michael Shapiro, U.S. Army Construction Engineering Research Laboratory
GRASS 6.0 updates: Radim Blazek, ITC-irst, Trento, Italy
Stream directions: Jaro Hofierka and Helena Mitasova
GRASS 6.3 code cleanup and label support: Brad Douglas

Last changed: $Date$