"Fix" incorrectly ordered rings using EvenOdd filltype

mapbox / mapnik-vector-tile

Mapnik implemention of Mapbox Vector Tile specification

BSD 3-Clause "New" or "Revised" License

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"Fix" incorrectly ordered rings using EvenOdd filltype #166

Closed springmeyer closed 8 years ago

springmeyer commented 8 years ago

This is a critical followup now that #161 is in place. For polygons with misordered rings we should test the clipping union with EvenOdd to ideally surface the true exterior ring.

flippmoke commented 8 years ago

Even odd should be exposed now externally -- this can now be tested downstream more.

In order to Fix winding order issues of other vector tiles three options should be set.

process_all_mp_rings: true
polygon_fill_type: even_odd_fill
multi_polygon_union: true

With all of these options all rings that are decoded from a vector tile and then re-encoded will be "fixed" to a current configuration with the data "corrected"