[Qgis-user] join by location

[Julie Pierson]

Hi all,

I have a question about the 'join by location' tool in ftools. Let's say 
I've got two polygon layers : a layer of provinces with the population 
for each province, and a layer of regions, each region resulting in the 
fusion of several provinces. Now I want to know the total population for 
each region, so I use the 'join by location' tool with my two layers, 
ticking the 'sum' box. My problem is that this tool takes into account 
for each region every province that has a common limit with the region : 
obviously that includes provinces not in the region, and it doesn't do 
what I want. Hope my example is clear.

I can see that behaving this way can be useful in some cases, but I 
think what I'm trying to do is also pretty standard stuff. Do you know 
if this is normal behaviour? Or am I doing something wrong?

I'm using QGIS 1.8.0.

Thanks a lot,

Julie.