## DESCRIPTION

v.extract 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.

## EXAMPLES

  v.extract -d list=1,2,3,4 input=soils output=soil_groupa type=area new=1

  Produces a new vector area file soil_groupa containing 'area' boundaries from soils 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.

  v.extract -d list=Abc,Def1,12A,WWd input=soils output=soil_groupa type=area new=0

  Produces a new vector area file soil_groupa containing 'area' boundaries from soils with area category labels of Abc,Def1, 12A,WWd; these labels correspond to numbers 1 thru 4 of soils. 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.

  v.extract input=soils output=soil_groupa type=area new=1 file=sample

  Produces a new vector area file soil_groupa containing 'area' boundaries from soils. No common boundaries are dissolved, all areas of the new map will be assigned category number 1.

  v.extract input=markveggy.shp output=markveggy.1 new=1 where="(VEGTYPE = 'Wi') or (VEGTYPE = 'PS') or (PRIME_TYPE='Wi')"

  Produces a new vector map with category label 1 if the SQL statement is fulfilled.

## SEE ALSO

GRASS SQL interface

## AUTHOR

R.L. Glenn, USDA, SCS, NHQ-CGIS

Last changed: $Date: 2005/02/13 22:38:03 $