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https://issues.apache.org/jira/browse/LUCENE-8220?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16412936#comment-16412936
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Karl Wright commented on LUCENE-8220:
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I think some of the communication disconnect we have been having is due to the
fact that I'm thinking that tiling of GeoConvexPolygon and GeoConcavePolygon is
really only applicable to polygons whose edges are fairly long to start with.
Polygons whose edge points are very close together is not the expected use case
of this approach; that is what GeoComplexPolygon is for.
The problem you demonstrate can still occur in a larger-scale polygon, but only
if there's a chance alignment between one edge and a point on the other side of
the polygon. My thinking, and the code I've committed is meant to deal with
that specific failure case, and not the case where the tinyness of the polygon
prevents *all* possible new edges from being created. I still have no idea how
to solve that problem.
It may be worth having the exception that is currently thrown recommend using
GeoComplexPolygon instead. Or, maybe the factory should automatically choose
that representation if we see that situation arise.
> GeoPolygon factory still shows problems with coplanar points
> ------------------------------------------------------------
>
> Key: LUCENE-8220
> URL: https://issues.apache.org/jira/browse/LUCENE-8220
> Project: Lucene - Core
> Issue Type: Bug
> Components: modules/spatial3d
> Reporter: Ignacio Vera
> Assignee: Karl Wright
> Priority: Major
> Attachments: concave.jpg, concaveWithTiling.jpg,
> coplanarity-test.patch, factory.patch
>
>
> The attached patch contains two polygons that still shows problems with
> co-planar points. To better explain the issue I attached some images:
> 1) concave.jpg: This is the polygon we want to build. Note that we want to
> build the concave part, therefore the blue part is actually not part of the
> shape and the white part is the area cover by the shape.
> 2) concaveWithTiling.jpg: The algorithm of the polygon factory tries to tile
> the polygon using convex polygons. In our case it creates the three colored
> polygons on the image. What it remains is a concave polygon.
> The problem with this polygon is that the right edge of the concave polygon
> contains co-planar points. These points cannot be merged into a single plane
> because they have different properties (internal edges or shape edges).
> Because GeoConvexPolygon and GeoConcavePolygon cannot handle polygons with
> co-planar points, the polygon cannot be built.
> [~kwri...@metacarta.com], Is it possible to make this polygons support such
> an extreme case?
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