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v.dissolve(1)		    GRASS GIS User's Manual		 v.dissolve(1)

NAME
       v.dissolve   -  Dissolves  boundaries  between adjacent areas sharing a
       common category number or attribute.

KEYWORDS
       vector, dissolve, area, line

SYNOPSIS
       v.dissolve
       v.dissolve --help
       v.dissolve  input=name	[layer=string]	  [column=name]	   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=nameA [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 ac-
	   cess	this is	the layer name.
	   Default: 1

       column=name
	   Name	of attribute column used to dissolve common boundaries

       output=nameA [required]
	   Name	for output vector map

DESCRIPTION
       The  v.dissolve	module is used to merge	adjacent areas in a vector map
       which share the same category value. The	resulting merged  area(s)  re-
       tains  this  category  value. Alternatively an integer or string	column
       can be defined which is used to find adjacent polygons  with  identical
       attribute  for  common boundary dissolving. In this case	the categories
       are not retained, only the values of the	new key	column.	See the	 v.re-
       class help page for details.

NOTES
       GRASS  defines a	vector area as composite entity	consisting of a	set of
       closed boundaries and a centroid. The centroids must contain a category
       number  (see v.centroids), this number is linked	to area	attributes and
       database	links.

       Multiple	attributes may be linked to a  single  vector  entity  through
       numbered	fields referred	to as layers. Refer to v.category for more de-
       tails.

       Merging of areas	can also be accomplished using v.extract -d which pro-
       vides  some  additional	options.   In  fact,  v.dissolve  is  simply a
       front-end to that module. The use of the	column parameter adds  a  call
       to v.reclass before.

EXAMPLES
   Basic use
       v.dissolve input=undissolved output=dissolved

   Dissolving based on column attributes
       North Carolina data set:
       g.copy vect=soils_general,mysoils_general
       v.dissolve mysoils_general output=mysoils_general_families column=GSL_NAME

   Dissolving adjacent SHAPE files to remove tile boundaries
       If tile boundaries of adjacent maps (e.g. CORINE	Landcover SHAPE	files)
       have to be removed, an extra step  is  required	to  remove  duplicated
       boundaries:
       # patch tiles after import:
       v.patch -e `g.list type=vector pat="clc2000_*" separator=","` out=clc2000_patched
       # remove	duplicated tile	boundaries:
       v.clean clc2000_patched out=clc2000_clean tool=snap,break,rmdupl	thresh=.01
       # dissolve based	on column attributes:
       v.dissolve input=clc2000_clean output=clc2000_final col=CODE_00

SEE ALSO
	v.category, v.centroids, v.extract, v.reclass

AUTHORS
       module:	M.  Hamish Bowman, Dept. Marine	Science, Otago University, New
       Zealand
       Markus Neteler for column support
       help page: Trevor Wiens

SOURCE CODE
       Available at: v.dissolve	source code (history)

       Main index | Vector index | Topics index	| Keywords index  |  Graphical
       index | Full index

       A(C) 2003-2020 GRASS Development	Team, GRASS GIS	7.8.3 Reference	Manual

GRASS 7.8.3							 v.dissolve(1)

NAME | KEYWORDS | SYNOPSIS | DESCRIPTION | NOTES | EXAMPLES | SEE ALSO | AUTHORS | SOURCE CODE

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