I need to produce a map of opposite semicircles or concentric circles to represent two numerical columns on the same map simultaneously. I have already tried to create a layer for each column's data and simply overlay it in QGIS. However the data ends up covering each other. The ideal would be to have different circles at the same point (concentric, but not overlapping) or opposite semicircles.
Objective: I want to create a map that compares an event in two different years but in the same place. So a semicircle would represent 2019 and another 2020.
I don't know if abroad this type of map carries the same name, so follow two examples:
I'm a student so I need the tools to be free. I only know how to work with QGIS and CARTO, but I can learn other tools as long as they are free.