![GRASS logo](grass_logo.png)
NAME
v.patch - Create a new vector map layer by combining other vector map layers.
KEYWORDS
vector
SYNOPSIS
v.patch
v.patch help
v.patch [-ae] input=name[,name,...] output=name [bbox=name] [--overwrite] [--verbose] [--quiet]
Flags:
- -a
- Append files to existing file (overwriting existing files must be activated)
- -e
- Copy also attribute table
- Only the table of layer 1 is currently supported
- --overwrite
- Allow output files to overwrite existing files
- --verbose
- Verbose module output
- --quiet
- Quiet module output
Parameters:
- input=name[,name,...]
- Name of input vector map(s)
- output=name
- Name for output vector map
- bbox=name
- Name for output vector map where bounding boxes of input vector maps are written to
DESCRIPTION
v.patch allows the user to combine any number of
vector maps together to create one composite vector
map. If the table structures are identical, attributes are
transferred to the new table.
NOTES
Any vectors that are duplicated among the maps being
patched together (e.g., border lines) will have to be
edited or removed after v.patch is run. Such
editing can be done automatically using
v.clean.
Lines may need to be
snapped with v.clean
tool=snap,break,rmdupl.
Boundaries may need to be cleaned with
v.clean tool=break,rmdupl,rmsa
repeatedly until the rmsa tool (Remove small angles at nodes)
no longer modifies any boundaries. If vector topology is still not
clean, boundaries may also need to be snapped with
v.clean tool=snap,break,rmdupl.
When using the -a flag, the user has to make sure that the
features in the different maps added to the output map do not have
overlapping category numbers, unless identical category numbers
reflect identical attributes, otherwise the attributes of the added
maps are lost. To avoid this, the user can use v.category
option=sum to change category values of some of the maps before
patching.
EXAMPLES
Patch together two maps with mixed feature types:
v.patch input=geology,streams out=geol_streams
Append one map to another:
g.copy vect=roads,transport
v.patch -a input=railroads output=transport --overwrite
SEE ALSO
v.clean,
v.build,
v.select,
v.overlay
AUTHORS
Dave Gerdes, U.S.Army Construction Engineering
Research Laboratory
Radim Blazek, ITC-Irst, Trento, Italy
Last changed: $Date: 2009-04-11 13:41:50 -0700 (Sat, 11 Apr 2009) $
Main index - vector index - Full index
© 2003-2010 GRASS Development Team