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:

                     attr - read values from attribute table (default)

                     cat  - read values from category

                     val  - use value specified by value option

                     z    - use z coordinate (points or contours only)

                     dir  - output as flow direction in degrees (lines only)

       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:

                     Labeled  areas  and/or  centroids  will  produce  filled  raster  coverages with edges that
                     straddle the original area boundary as long as the boundary is NOT labeled.
                     (Use v.category option=del type=boundary to remove.)

                     Labeled lines and boundaries will produce lines of raster cells which  touch  the  original
                     vector line. This tends to be more aggressive than area-only conversions.

                     Points  and  orphaned centroids will be converted into single cells on the resultant raster
                     map.

       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) $

       Full index

       © 2003-2013 GRASS Development Team

GRASS 6.4.3                                                                                    v.to.rast(1grass)