What about Vector Geoprocessing tools Dissolve
With this tool, you are able to process 'only selected features',
which could be done ahead of time for the countries you wish to
dissolve further.
This is a Python tool, so for extremely large datasets it might be a bit slow...
Carson
On Mon, May
Hi
I would create a new field in the attribute table to be filled with the
condition. I believe the simplest way is to use a dbf editor (like openoffice
spreadsheet or old versions of excel) to create the condition field (same code
for shapes to be dissolved). Then I would use the Dissolve
Good point Pedro, my suggestion wouldn't output all the required
features, only those that were initially selected... You can of course
also edit the table in QGIS if you are using a relatively recent
version, which supports adding fields and a field calculator.
Carson
On Mon, May 24, 2010 at
