## DESCRIPTION

v.db.droprow removes vector object(s) (point, line, area, face etc.) from a vector map through attribute selection in the table connected to the given vector map. It automatically checks the connection for the specified layer.

## NOTES

v.db.droprow is a front-end to v.extract (reverse selection) to allow easier usage. The existing database connection(s) can be verified with v.db.connect.

## EXAMPLES

Dropping all vector points without elevation attribute (North Carolina data set):

    g.region rast=elevation -p
    v.random output=rand5k_elev n=5000

    v.db.addtable map=rand5k_elev column="elevation double precision"
    v.what.rast vect=rand5k_elev rast=elevation column=elevation

    # verify absence of some elevation attributes ("number of NULL attributes"):
    v.univar rand5k_elev type=point column=elevation

    # Remove all vector points lacking elevation attribute
    v.db.droprow rand5k_elev output=rand5k_elev_filt where="elevation IS NULL"

    # verify:
    v.univar rand5k_elev_filt type=point column=elevation

## SEE ALSO

db.droptable, db.execute, v.db.addcolumn, v.db.addtable, v.db.connect, v.db.dropcolumn, v.db.droptable, v.db.select, v.db.update

## AUTHOR

Markus Neteler

Last changed: $Date$