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From "Karl Wright (JIRA)" <j...@apache.org>
Subject [jira] [Comment Edited] (LUCENE-6759) Integrate lat/long BKD and spatial 3d, part 2
Date Sat, 22 Aug 2015 12:16:45 GMT

    [ https://issues.apache.org/jira/browse/LUCENE-6759?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14708013#comment-14708013
] 

Karl Wright edited comment on LUCENE-6759 at 8/22/15 12:16 PM:
---------------------------------------------------------------

Thinking through why one error measure just doesn't work in this case:

(1) The point in question is on the wrong side of the GeoCircle plane, and is pretty nearly
the *closest* point on the XYZSolid to the GeoCircle plane.
(2) The slight tilt of the GeoCircle plane is enough to put the upper intersection point beyond
the MINIMUM_RESOLUTION distance (at a distance of roughly 1e-8).  That removes the first candidate
intersection point from consideration.
(3) Because the GeoCircle is almost at the edge of the world, the slope between the GeoCircle
plane and the planet surface is quite high, so a small error distance in X translates to a
large distance in Y or Z.  That allows the second candidate intersection point to be removed
from consideration.

The obvious conclusion is that we can tolerate no error at all in determining if a point is
within a shape or not, for the purposes of evaluating relationships.  It's not clear to me
yet whether we need to simply tighten the existing definition of "isWithin()", or we need
to have multiple variants of "isWithin()".  Further analysis is needed to figure that out.



was (Author: kwright@metacarta.com):
Thinking through why one error measure just doesn't work in this case:

(1) The point in question is on the wrong side of the GeoCircle plane, and is pretty nearly
the *closest* point on the XYZSolid to the GeoCircle plane.
(2) The slight tilt of the GeoCircle plane is enough to put the upper intersection point beyond
the MINIMUM_RESOLUTION distance (at a distance of roughly 1e-8).  That removes the first candidate
intersection point from consideration.
(3) Because the GeoCircle is almost at the edge of the world, the slope between the GeoCircle
plane and the planet surface is quite high, so a small error distance in X translates to a
large distance in Y or Z.  That allows the second candidate intersection point to be removed
from consideration.



> Integrate lat/long BKD and spatial 3d, part 2
> ---------------------------------------------
>
>                 Key: LUCENE-6759
>                 URL: https://issues.apache.org/jira/browse/LUCENE-6759
>             Project: Lucene - Core
>          Issue Type: New Feature
>            Reporter: Michael McCandless
>
> This is just a continuation of LUCENE-6699, which became too big.



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