[Gdal-dev] Dissolving internal boundaries

[Hamish]

> Is there any way with gdal/ogr tools to join polygons into a single
> polygon based upon a .dbf attribute and dissolve the interior
> boundaries of constituent shapefile polygons?

fwiw, this is possible in GRASS GIS 6.2 with the v.dissolve module.

it dissolves by category (feature ID) so you'll want reset the cat
column to whatever integer column in the DBF with v.reclass. Or,
(harder) if the common attribute isn't an integer, create a new column
(v.db.addcol) and populate it with a unique integer which refers to each
attribute, then v.reclass & v.dissolve as above.

using a second "layer" (attached DBF) might be a better way
(v.db.addcol) vs adding an additional column to your attribute table.

see also v.category, v.to.db, and v.distance.

if you figure out a good method for "the hard way", let me know & I'll
add it to v.dissolve as a new option.


Hamish