I am using QGIS 3.8 and I am using a layer from OSM of Tokyo city. The layer is consisted from many polygons and I have tried to merge it but I got error. This is how the original layer was look like:
When I have checked the geometry validity no error appeard on the problematic areas, beside this one that appeard on area that I manage to merge. I have tried to check but couldn't find any visible error:
I really don't know how to fix it and how to merge the "green layers" with the pink ones. I have seen previous messages in this forum but they were using scripts.
any idea ?