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v.to.rast.1grass
Langue: en
Version: 330927 (ubuntu - 24/10/10)
Section: 1 (Commandes utilisateur)
NAME
v.to.rast - Converts a binary GRASS vector map into a GRASS raster map .KEYWORDS
vector, raster, conversionSYNOPSIS
v.to.rastv.to.rast help
v.to.rast input=name output=name [use=string] [type=string[,string,...]] [layer=integer] [column=name] [value=float] [rows=integer] [rgbcolumn=name] [labelcolumn=name] [--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- 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)- type=string[,string,...]
Feature type
Options: point,line,area
Default: point,line,area- layer=integer
Layer number
A single vector map can be connected to multiple database tables. This number determines which table to use.
Default: 1- column=name
Name of column for attr parameter (data type must be numeric)- value=float
Raster value
Default: 1- rows=integer
Number of rows to hold in memory
Default: 4096- rgbcolumn=name
Name of color definition column (with RRR:GGG:BBB entries)- labelcolumn=name
Name of column used as raster category labels
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 tabledb.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.categoryAUTHORS
Original code: Michael Shapiro, U.S. Army Construction Engineering Research LaboratoryGRASS 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: 2008-02-19 21:12:24 +0100 (mar, 19 feb 2008) $
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