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Man Pages
v.db.droprow(1) Grass User's Manual v.db.droprow(1)

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

vector, attribute table, database

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

--overwrite
 
Allow output files to overwrite existing files
--help
 
Print usage summary
--verbose
 
Verbose module output
--quiet
 
Quiet module output
--ui
 
Force launching GUI dialog

input=name [required]
 
Name of input vector map
 
Or data source for direct OGR access
layer=string
 
Layer number or name
 
Vector features can have category values in different layers. This number determines which layer 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 population >= 10000
output=name [required]
 
Name for output vector map

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.

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.

Dropping all vector points without elevation attribute (North Carolina data set):
 
 
g.region raster=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

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

Markus Neteler
Last changed: $Date: 2014-12-19 22:17:36 +0100 (Fri, 19 Dec 2014) $

Available at: v.db.droprow source code (history)
Main index | Vector index | Topics index | Keywords index | Graphical index | Full index
© 2003-2018 GRASS Development Team, GRASS GIS 7.4.3 Reference Manual
GRASS 7.4.3

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