
NAME
v.db.droprow - Removes a vector object (point, line, area, face etc.) 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 output=name [layer=integer] where=string [--overwrite] [--verbose] [--quiet]
Flags:
- --overwrite
- Allow output files to overwrite existing files
- --verbose
- Verbose module output
- --quiet
- Quiet module output
Parameters:
- input=name
- Vector map for which to drop vector objects
- output=name
- Name for output vector map
- layer=integer
- Layer of attribute table to use for selection
- Default: 1
- where=string
- WHERE conditions for vector delete, without 'where' keyword (e.g. "elevation IS NULL")
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 (Spearfish data set):
g.region rast=elevation.10m
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.10m 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: 2009-11-26 13:51:15 -0800 (Thu, 26 Nov 2009) $
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