Joining attributes from two different polygon layers

Question

I'm trying to join the attributes from the polygon layers shown on the images.

The result I'm looking for is one layer that contains the square and the attributes of both triangles: the triangles are perfectly overlapped with the square.

I've tried to use "Join attributes by location" but the output layer is not what I'm looking for as it contains two overlapped squares one for each triangle.

Also, I've tried to intersect the layers but the result are two triangles and to join the vectorial layers but the result is again two triangles.

Answer 1

Your problem is that you want to join the attributes of two geometries in one. This will create a conflict with the fields name (they must be double to realise what you are looking for).

The best solution should be to run two times "Join attributes by location" using only one selected triangle for time.

Run a first time selection one triangle and using your triangle layer as Base layer. In the parameters be sure that you activate Selected features only for the Triangles layer and, in Joined field prefix use '1_'.

Run now a second time the algorithm selection the other triangle and using as Base layer the temporary layer created by the precedent operation, and in in Joined field prefix use '2_' to create different fields.