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
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)?