differencesqgisvector
Is there a way to do a 1:1 difference between two polygon layers based on a similar attribute? The layers have the same number of features with a shared attribute. I've tried the native QGIS difference algorithm but it subtracts from the features of the first layer, the dissolved/merged area of the second layer.
Edit: Added photo showing sample layers.
Yes, you need a layer that covers the same area to calculate the difference. The easiest way is to create a buffer around the centerpoint.
If you already have a layer that includes a point feature at the centerpoint, you can select that and then use the Vector/Geprocessing/Buffer tool with the "Use only selected features" check box activated.
If you don't have a point feature at the centerpoint, you can create a new point shapefile and adding a point, probably using the Numerical Digitize plugin to get an accurate position of the point. Then you can run the Buffer tool on that layer.
As @user30184 mentioned, there are errors in your "input_layer". You can use the GRASS tool v.clean to clean most of the errors. Use the break option with a threshold of 0.1. This should 'break' your single polygon into multiple polygons (you can uncheck the Errors output as you don't really need this):
If you want, could dissolve this based on an attribute field (doesn't matter which, all values are the same). I also found it easier to merge all your "difference_layers" using Vector > Data Management Tools > Merge Shapefiles to One:
Finally, you should be able to run the difference tool now using your newly cleaned and merged layers:
Hope this helps!
Best Answer
Assuming that you have a polygon layer named 'polygonsA', with a field named 'idA'; and you want to make the difference between any feature of that layer and the feature of the polygon layer 'polygonsB' that have the same (idA) value in the field 'idB'.
It is possible in a simple way as long as there is a single feature in polygonsB for each value of the attribute. If not, Dissolve first the polygonsB layer by the idB field.
Open the Geometry by expression tool.
Select polygonsA as input layer.
Select Polygon as output geometry type.
Write the following geometry expression:
The output is a polygon layer named 'Modified geometry' with the difference by attribute between polygonsA and polygonsB.