[GRASS5] 5.7 how to merge polygons with same attribute ?

[Radim Blazek]

Moritz Lennert wrote:
> Hello,
> 
> How do I merge polygons with the same value for a given attribute in the
> attribute table ?
> 
> For example: if I have a map of the world by countries, and for each country
> an attribute "continent" in the database table with values such as "Europe",
> "North America", etc, how could I create a map showing only the outlines of
> the continents ?

v.reclass.

Radim