Generate a layer of rose histograms based on a provided (polygon) tile layer

[havatv]

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:

[havatv]

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.

[havatv]

Support for tiles was added in 34c941626a1fef4beb7a6309b6487cb9e3465923.