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<h2>DESCRIPTION</h2>
<em>v.to.rast</em> transforms GRASS vector map
layers into GRASS raster map layer format.
<h2>NOTES</h2>
<em>v.to.rast</em> will only affect data in areas lying
inside the boundaries of the current geographic region.
Before running <em>v.to.rast</em>, the user should
therefore ensure that the current geographic region is
correctly set and that the region resolution is at the
desired level.
<p>
Either the <em><b>col</b></em> parameter or the <em><b>value</b></em>
parameter must be specified.
<P>
The <em><b>col</b></em> 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 <em><a href="db.describe.html">db.describe</a></em>.
<P>
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
<a href="v.category.html">v.category option=add</a>).
<P>
Otherwise:
<LI>
Labeled areas and/or centroids will produce filled raster coverages with edges
that straddle the original area boundary <b>as long as the boundary is NOT
labeled</b>.
<BR>(Use <tt>v.category option=del type=boundary</tt> to remove.)
<LI>
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.
<LI>
Points and orphaned centroids will be converted into single cells on the
resultant raster map.
<h2>EXAMPLE</h2>
<em>Convert a vector map and use column SPEED from attribute table</em><br>
<b>db.describe -c table=</b><em>vect_map</em>
<pre>
ncols:3
Column 1: CAT
Column 2: SPEED
Column 3: WIDTH
</pre>
<b>v.to.rast in=</b><em>vect_map</em> <b>out=</b><em>raster_map</em>
<b>col=</b><em>SPEED</em>
<h2>AUTHORS</h2>
Michael Shapiro,
U.S. Army Construction Engineering
Research Laboratory
<br>
Radim Blazek, ITC-Irst, Trento, Italy
<p><i>Last changed: $Date: 2004/06/01 03:56:02 $</i>
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