v.db.droprow.1grass - Man Page
Removes a vector feature from a vector map through attribute selection.
Keywords
vector, attribute table, database
Synopsis
v.db.droprow
v.db.droprow --help
v.db.droprow input=name [layer=string] where=sql_query output=name [--overwrite] [--help] [--verbose] [--quiet] [--ui]
Flags
- --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
Parameters
- 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
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 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=elevationSee 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
GRASS SQL interface
Author
Markus Neteler
Source Code
Available at: v.db.droprow source code (history)
Accessed: Saturday Nov 09 07:56:31 2024
Main index | Vector index | Topics index | Keywords index | Graphical index | Full index
© 2003-2024 GRASS Development Team, GRASS GIS 8.4.0 Reference Manual