[Qgis-user] Qgis-user mailing list

Brent Wood Brent.Wood at niwa.co.nz
Mon Jan 11 16:57:48 PST 2021

You should be able to intersect the two layers, but may have issues if they are in different CRS's, or there are topological errors present.

If they are in different CRS's, then export one to the CRS of the other, and generate the intersection with that one.

Also run Vector-> Geometry tools -> Check validity on each source layer to ensure the data is valid.

The result should be a layer that has all the polygons from one split by the other to form new polygons common to both layers, and with each of the new polygons having all the attributes from both original layers.

Note that if you need to include the areas in the source layers that are not common to both, you'll need to get the differences between the layers (both A-B & B-A) and add these to the intersection.

Note that this is essentially a spatial data management question, and while QGIS can do it perfectly well, I find it can be easier to manage the data in Postgis tables in a database, and use Postgis SQL statements to do this, using QGIS to see the resulting data in the map canvas.


Brent Wood

Principal Technician, Fisheries
DDI:  +64 (4) 3860529

From: Qgis-user <qgis-user-bounces at lists.osgeo.org> on behalf of Per-Ove Persson <perovelpersson at gmail.com>
Sent: Monday, January 11, 2021 09:37
To: Qgis-user at lists.osgeo.org <Qgis-user at lists.osgeo.org>
Subject: [Qgis-user] Qgis-user mailing list

Hi !

I am very new user of QGIS. And now have I run into difficulties.

Use the QGIS version 3.10.10

I try to combine two layers in order to receive agriculture area per different municipalities

It seams that I do something wrong because I am not able to do that.

Do somebody have any nice and clever solution in order to solve this I would be grateful

Best Regards

Per-Ove Persson

Brent Wood
Principal Technician - GIS and Spatial Data Management
Programme Leader - Environmental Information Delivery
+64-4-386-0529 |
National Institute of Water & Atmospheric Research Ltd (NIWA)
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