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NAME

v.to.rast - Converts (rasterize) a vector map into a raster map.

KEYWORDS

vector, raster, conversion

SYNOPSIS

v.to.rast
v.to.rast help
v.to.rast input=name [layer=integer] [type=string[,string,...]] output=name use=string [column=name] [rgbcolumn=name] [labelcolumn=name] [value=float] [rows=integer] [--overwrite] [--verbose] [--quiet]

Flags:

--overwrite
Allow output files to overwrite existing files
--verbose
Verbose module output
--quiet
Quiet module output

Parameters:

input=name
Name of input vector map
layer=integer
Layer number
A single vector map can be connected to multiple database tables. This number determines which table to use.
Default: 1
type=string[,string,...]
Feature type
Options: point,line,area
Default: point,line,area
output=name
Name for output raster map
use=string
Source of raster values
Options: attr,cat,val,z,dir
Default: attr
attr: read values from attribute table
cat: use category values
val: use value specified by value option
z: use z coordinate (points or contours only)
dir: output as flow direction (lines only)
column=name
Name of column for 'attr' parameter (data type must be numeric)
rgbcolumn=name
Name of color definition column (with RRR:GGG:BBB entries)
labelcolumn=name
Name of column used as raster category labels
value=float
Raster value (for use=val)
Default: 1
rows=integer
Number of rows to hold in memory
Default: 4096

DESCRIPTION

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

NOTES

v.to.rast will only affect data in areas lying inside the boundaries of the current geographic region. Before running v.to.rast, 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).

Otherwise:

Flow directions are given in degrees counterclockwise from east.

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

EXAMPLES

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

ncols:3
Column 1: CAT
Column 2: SPEED
Column 3: WIDTH 
v.to.rast in=vect_map out=raster_map col=SPEED

2. Calculate stream directions from a river vector map (Spearfish)

v.to.rast in=streams out=streamsdir use=dir

3. Convert a vector polygon map to raster including descriptive labels (Spearfish)

v.to.rast in=fields out=myfields use=attr col=cat labelcol=label
r.category myfields

SEE ALSO

db.describe, v.category

AUTHORS

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: 2011-11-08 03:29:50 -0800 (Tue, 08 Nov 2011) $


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