I have two layers:
Layer 1 - containing municipalities of country X in the year 2014 (around 600)
Layer 2 - containing municipalities of country X in the year 2018 (around 500)
Between 2014-2018 several municipalities have merged. E.g. municipality A, B and C in the 2014 layer no longer exist in 2018 but are now part of municipality D.
I want to know for each 2014 municipality what its corresponding 2018 municipality is. So for municipality A, B and C the outcome should be D.
I tried to achieve this by performing Join by Location (using intersect). I would expect the joined layer to have 600 features (i.e. the number of 2014 municipalities) with a new attribute containing the corresponding 2018 municipality. However, the joined layer I get has over 2400 features. Municipality A is present 4 times, one entry has municipality D as new attribute (as expected) but the other 3 entries have the neighbouring municipalities of A as new attribute (E, F and I). I.e. QGIS seems to think that municipality A does not only intersect with D but also with all neighbouring municipalities of A.
Am I doing something wrong here?
Both layers have the same CRS.
Edit: Found out that if I zoom in a lot (ratio 85:1) there's a small difference between the two layers. I guess this causes the issue.