A user would like to generate separate rose diagrams for different parts of the map, and present the rose diagrams over the corresponding part of the map (as a new layer). The parts could be provided using a polygon layer.
The result would look like this:
The user can now supply a polygon layer that define the "tiles" (could be overlapping). For each tile, a rose diagram (stored as an SVG file) is generated. The rose diagrams are used to style a point layer created from the polygon tile layer.