NAME
v.db.droprow - 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
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
GRASS SQL interface
Markus Neteler
SOURCE CODE
Available at:
v.db.droprow source code
(history)
Latest change: Thursday Feb 03 11:10:06 2022 in commit: 547ff44e6aecfb4c9cbf6a4717fc14e521bec0be
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GRASS Development Team,
GRASS GIS 8.2.2dev Reference Manual