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NAME

v.db.droprow - Removes a vector feature from a vector map through attribute selection.

KEYWORDS

vector, database, attribute table

SYNOPSIS

v.db.droprow
v.db.droprow help
v.db.droprow input=name layer=string where=sql_query output=name [--overwrite] [--verbose] [--quiet]

Flags:

--overwrite
Allow output files to overwrite existing files
--verbose
Verbose module output
--quiet
Quiet module output

Parameters:

input=name [required]
Name of input vector map
Or data source for direct OGR access
layer=string [required]
Layer number or name
A single vector map can be connected to multiple database tables. This number determines which table to use. When used with direct OGR access this is the layer name.
Default: 1
where=sql_query [required]
WHERE conditions of SQL statement without 'where' keyword
Example: income < 1000 and inhab >= 10000
output=name [required]
Name for output vector map

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.dropcol, v.db.droptable, v.db.select, v.db.update

AUTHOR

Markus Neteler

Last changed: $Date: 2011-09-29 12:18:47 -0700 (Thu, 29 Sep 2011) $

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