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https://issues.apache.org/jira/browse/LUCENE-6477?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14547918#comment-14547918
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David Smiley commented on LUCENE-6477:
--------------------------------------
Mike,
This looks cool; it's been on my backlog of interesting patches to look at.
But I noticed it's not in the spatial module and doesn't have "spatial" in the
package. Can you please explain to me your rationale why this is so? We have
3 highlighters that have no APIs in common in the highlighter module, we've got
lots of suggesters in the suggest module... why wouldn't all spatial
capabilities be in the spatial module? It needn't fit any interface or have
the same dependencies as anything else in the spatial module. The modules are
both an organizational construct and it reduces the total 'jar' weight for
those that don't need what's in any one module. I could imagine "sandbox"
being an alternative destination if you feel that's appropriate.
> Add BKD tree for spatial shape query intersecting indexed points
> ----------------------------------------------------------------
>
> Key: LUCENE-6477
> URL: https://issues.apache.org/jira/browse/LUCENE-6477
> Project: Lucene - Core
> Issue Type: New Feature
> Reporter: Michael McCandless
> Assignee: Michael McCandless
> Fix For: Trunk, 5.2
>
> Attachments: LUCENE-6477.patch, LUCENE-6477.patch
>
>
> I'd like to explore using dedicated spatial trees for faster shape
> intersection filters than postings-based implementations.
> I implemented the tree data structure from
> https://www.cs.duke.edu/~pankaj/publications/papers/bkd-sstd.pdf
> The idea is simple: it builds a full binary tree, partitioning 2D
> space, alternately on lat and then lon, into smaller and smaller
> rectangles until a leaf has <= N (default 1024) points.
> It cannot index shapes (just points), and can then do fast shape
> intersection queries. Multi-valued fields are supported.
> I only implemented the "point is contained in this bounding box" query
> for now, but I think polygon shape querying should be easy to
> implement using the same approach from LUCENE-6450.
> For indexing, you add BKDPointField (takes lat, lon) to your doc, and
> must set up your Codec use BKDTreeDocValuesFormat for that field.
> This DV format wraps Lucene50DVFormat, but then builds the disk-based
> BKD tree structure on the side. BKDPointInBBoxQuery then requires this
> DVFormat, and casts it to gain access to the tree.
> I quantize each incoming double lat/lon to 32 bits precision (so 64
> bits per point) = ~9 milli-meter lon precision at the equator, I
> think.
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