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https://issues.apache.org/jira/browse/LUCENE-6699?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14646068#comment-14646068
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Michael McCandless commented on LUCENE-6699:
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bq. you ARE after all describing a second surface shape by your x-y-z ranges
That's exactly it. Essentially the BKD tree needs a way to recursively chop up
the earth surface into smaller and smaller curved-rectangle-like (I think?)
shapes on the earth's surface, both at indexing time and at search time.
At search time, for a given cell, it needs to "relate" to the query shape to
know if the query shape full contains the cell, does not overlap with the cell,
or partially overlaps.
But I don't understand the "degenerate in X/Y" Area objects... it seems like
GeoArea would be used for the lat/lon "approximation" (outer bounding box?) to
a GeoShape? Seems like it's better if we can do all functions using proper
earth-surface shapes? Sorry this is still all very new to me :)
> Integrate lat/lon BKD and spatial3d
> -----------------------------------
>
> Key: LUCENE-6699
> URL: https://issues.apache.org/jira/browse/LUCENE-6699
> Project: Lucene - Core
> Issue Type: New Feature
> Reporter: Michael McCandless
> Assignee: Michael McCandless
>
> I'm opening this for discussion, because I'm not yet sure how to do
> this integration, because of my ignorance about spatial in general and
> spatial3d in particular :)
> Our BKD tree impl is very fast at doing lat/lon shape intersection
> (bbox, polygon, soon distance: LUCENE-6698) against previously indexed
> points.
> I think to integrate with spatial3d, we would first need to record
> lat/lon/z into doc values. Somewhere I saw discussion about how we
> could stuff all 3 into a single long value with acceptable precision
> loss? Or, we could use BinaryDocValues? We need all 3 dims available
> to do the fast per-hit query time filtering.
> But, second: what do we index into the BKD tree? Can we "just" index
> earth surface lat/lon, and then at query time is spatial3d able to
> give me an enclosing "surface lat/lon" bbox for a 3d shape? Or
> ... must we index all 3 dimensions into the BKD tree (seems like this
> could be somewhat wasteful)?
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