[
https://issues.apache.org/jira/browse/LUCENE-8280?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16457557#comment-16457557
]
Karl Wright commented on LUCENE-8280:
-------------------------------------
Hmm, [~ivera], I've concluded that the flaw is really more subtle.
Effectively, it is not possible to count crossings starting on an edge and come
up with a good number. It's straightforward to prove this, in retrospect --
which is probably why I created the DualCrossingIterator in the first place,
because it doesn't suffer from this problem, because we can guarantee that
neither the start point nor the end point is on a polygon edge.
Of course, the reason that I got rid of the DualCrossingIterator was because it
cannot be readily modified to allow travel on any one leg of a full 180
degrees, so it has its own problems.
The good news is that we can readily detect when we've picked a bad choice for
travel planes. The bad news is that there is no guarantee we can find a *good*
choice.
As far as a strategy going forward, here's my thought:
- Basic strategy: Try a number of approaches, and hope that one eventually
succeeds.
- When we try an approach, we throw IllegalArgumentException if we find
ourselves with a bad intersection point.
- With two test points, there are two choices of intersection point immediately
available. But if we restructure the code a bit, there are at least three
choices available per test point, barring those excluded because they are too
close to the world edge.
- We can also resurrect the DualCrossingIterator, to include as part of our
"strategy mix", provided it knows how to error out of someone tries to use it
for too big a leg.
> Repeatable failure for GeoConvexPolygons
> ----------------------------------------
>
> Key: LUCENE-8280
> URL: https://issues.apache.org/jira/browse/LUCENE-8280
> Project: Lucene - Core
> Issue Type: Bug
> Components: modules/spatial3d
> Reporter: Karl Wright
> Assignee: Karl Wright
> Priority: Major
>
> Reproduce with:
> {code}
> ant test -Dtestcase=TestGeo3DPoint -Dtests.method=testGeo3DRelations
> -Dtests.seed=1F49469C1989BC0 -Dtests.slow=true -Dtests.badapples=true
> -Dtests.locale=fr-BE -Dtests.timezone=Europe/Malta -Dtests.asserts=true
> -Dtests.file.encoding=Cp1252
> {code}
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org
For additional commands, e-mail: dev-h...@lucene.apache.org
