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) retains
this category value.
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.
(GRASS Shell Script)
EXAMPLES
Basic use
v.dissolve input=undissolved output=dissolved
Dissolving based on column attributes
# check column names:
v.info -c polbnda_italy
# reclass based on desired column:
v.reclass polbnda_italy out=polbnda_italy_recl_nam col=vmap_nam
# dissolve:
v.dissove input=polbnda_italy_recl_nam output=pol_italy_regions
SEE ALSO
v.category,
v.centroids,
v.extract,
v.reclass
AUTHORS
module: M. Hamish Bowman, Dept. Marine Science, Otago University, New Zealand
help page: Trevor Wiens
Last changed: $Date$