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<h2>DESCRIPTION</h2>
<em>v.extract</em> allows a user to select vector objects from an existing
vector map and creates a new map containing only the selected objects.
Database tables can be queried with SQL statements, if a connection is
established.
Dissolving (optional) is based on the output categories. If 2 adjacent
areas have the same output category, the boundary is removed.
<h2>EXAMPLES</h2>
<DL>
<dd><b>v.extract -d list=</b>1,2,3,4
<b>input=</b>soils <b>output=</b>soil_groupa <b>type=</b>area <b>new=</b>1
<p>
Produces a new vector area file <em>soil_groupa</em> containing 'area'
boundaries from <em>soils</em> with area category numbers of 1 thru 4; any
common boundaries are dissolved, and all areas of the new map will be
assigned category number 1.
<p>
<dt>
<dd><b>v.extract -d list=</b>Abc,Def1,12A,WWd
<b>input=</b>soils <b>output=</b>soil_groupa <b>type=</b>area <b>new=</b>0 </b>
<p>
Produces a new vector area file <em>soil_groupa</em> containing 'area'
boundaries from <em>soils</em> with area category labels of Abc,Def1, 12A,WWd;
these labels correspond to numbers 1 thru 4 of <em>soils</em>. Any common
boundaries are dissolved, all areas of the new map will be retain their
original category numbers 1 thru 4, in this case, since new was set to
0.
<p>
<dt>
<dd><b>v.extract input=</b>soils <b>output=</b>soil_groupa
<b>type=</b>area <b>new=</b>1 <b>file=</b>sample
<p>
Produces a new vector area file <em>soil_groupa</em> containing 'area'
boundaries from <em>soils</em>. No common boundaries are dissolved, all areas
of the new map will be assigned category number 1.
<!-- The -n flag doesn't exist.
The "labels" (-n option) can be found in the file sample of the current directory.
-->
<p>
<dt>
<dd><b>v.extract input=</b>markveggy.shp <b>output</b>=markveggy.1
<b>new=</b>1 <b>where=</b>"(VEGTYPE = 'Wi') or (VEGTYPE = 'PS') or (PRIME_TYPE='Wi')"
<p>
Produces a new vector map with category label 1 if the SQL statement is
fulfilled.
</DL>
<h2>SEE ALSO</h2>
<em><a HREF="sql.html">GRASS SQL interface</a></em>
<h2>AUTHOR</h2>
R.L. Glenn, USDA, SCS, NHQ-CGIS
<p><i>Last changed: $Date: 2005/02/13 22:38:03 $</i>
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