[Qgis-user] ftools union issue: duplicating polygons

[Giovanni Manghi]

Would you mind adding your notes and data here

http://hub.qgis.org/issues/4567

thanks

-- Giovanni --

> Hello all:
>
> I'm having some problems using union from fTools 0.6.2, specifically with Union.
>
> I have three polygon layers:
> a municipality area
> 1980 urban areas
> 1990 urban areas
>
> The first union process (1990 + municipal polygon) was OK.
>
> Then the second union gave me problems.
> It seems that union produced duplicated polygons.  I could see that when using transparency.
> This map should be equally transparent.
>
> I made two simple fake polygons over the same area and it went well with union.
>
> I've enclosed the shapefiles if anyone is interested in this issue.