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From "Karl Wright (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (LUCENE-6196) Include geo3d package, along with Lucene integration to make it useful
Date Mon, 02 Feb 2015 06:57:34 GMT

    [ https://issues.apache.org/jira/browse/LUCENE-6196?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14300944#comment-14300944
] 

Karl Wright commented on LUCENE-6196:
-------------------------------------

bq: There's one thing I want to confirm with you Karl: so these shares are "accurate" to the
spherical model (the unit sphere)? That is, if I have say a line string, then is each line
segment a great-circle path between its start & end? If not then can you please explain?

In part this depends on the shape.  For GeoConvexPolygons, the surface paths are all great
circles.  For GeoCircles, it's a circle not a great circle.  For GeoPaths, the boundary of
the shape consists of a zone of a specific width on either side of a great circle, so the
boundary is not (if you think about it) actually a great circle.  For GeoBBox shapes (e.g.
GeoRectangles), they are great circles in longitude, but horizontal slices in latitude.  This
matches the standard "rectangle" metaphor that quad trees are built on.

> Include geo3d package, along with Lucene integration to make it useful
> ----------------------------------------------------------------------
>
>                 Key: LUCENE-6196
>                 URL: https://issues.apache.org/jira/browse/LUCENE-6196
>             Project: Lucene - Core
>          Issue Type: New Feature
>          Components: modules/spatial
>            Reporter: Karl Wright
>            Assignee: David Smiley
>         Attachments: ShapeImpl.java, geo3d-tests.zip, geo3d.zip
>
>
> I would like to explore contributing a geo3d package to Lucene.  This can be used in
conjunction with Lucene search, both for generating geohashes (via spatial4j) for complex
geographic shapes, as well as limiting results resulting from those queries to those results
within the exact shape in highly performant ways.
> The package uses 3d planar geometry to do its magic, which basically limits computation
necessary to determine membership (once a shape has been initialized, of course) to only multiplications
and additions, which makes it feasible to construct a performant BoostSource-based filter
for geographic shapes.  The math is somewhat more involved when generating geohashes, but
is still more than fast enough to do a good job.



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