ÐÐÐСÐÐÐÐ

   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)
   retains this category value. Optionally, a column can be defined which
   is used to find adjacent polygons with identical attribute for common
   boundary dissolving. 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 details.

   Merging of areas can also be accomplished using "v.extract -d" which
   provides 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.

   (GRASS Shell Script)

ÐÐ ÐÐÐРЫ

  Basic use

v.dissolve input=undissolved output=dissolved

  Dissolving based on column attributes

# check column names:
v.info -c polbnda_italy

# dissolve based on column attributes:
v.dissolve input=polbnda_italy output=pol_italy_regions col=vmap_nam

  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.mlist type=vect pat="clc2000_*" sep=,` 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

СÐ. ТÐÐÐÐ

   [1]v.category, [2]v.centroids, [3]v.extract, [4]v.reclass

ÐÐТÐРЫ

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

   Last changed: $Date: 2007-03-04 12:13:15 -0600 (ÐÑ, 04 Ð¼Ð°Ñ 2007) $

ÐвÑÐ¾Ñ Ð¿ÐµÑевода

References

   1. file://localhost/root/tmp/2/fin/v.category.html
   2. file://localhost/root/tmp/2/fin/v.centroids.html
   3. file://localhost/root/tmp/2/fin/v.extract.html
   4. file://localhost/root/tmp/2/fin/v.reclass.html