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NAME

       v.patch  - Creates a new vector map by combining other vector maps.

KEYWORDS

       vector, geometry, level1

SYNOPSIS

       v.patch
       v.patch --help
       v.patch  [-nzeab] input=name[,name,...] output=name  [bbox=name]   [--overwrite]  [--help]
       [--verbose]  [--quiet]  [--ui]

   Flags:
       -n
           Do not expect input with topology
           Applicable when input is points without topology

       -z
           Expect z coordinate even when not using topology
           Applicable when input is points with z coordinate but without topology

       -e
           Copy also attribute table
           Only the table of layer 1 is currently supported

       -a
           Append files to existing file (overwriting existing files must be activated)

       -b
           Do not build topology
           Advantageous when handling a large number of points

       --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[,name,...] [required]
           Name of input vector map(s)
           Or data source(s) for direct OGR access

       output=name [required]
           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  -e  flag,  v.patch  shifts  category  (cat) values in the output so that
       category numbers from the different input maps do not overlap. This shift  is  applied  to
       both  the category values of the features and the category values in the attribute tables.
       Hence, there is no need to run v.category and v.db.update beforehand.

       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: 2018-11-01 08:54:25 +0100 (Thu, 01 Nov 2018) $

SOURCE CODE

       Available at: v.patch source code (history)

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       © 2003-2019 GRASS Development Team, GRASS GIS 7.6.1 Reference Manual