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https://issues.apache.org/jira/browse/LUCENE-4978?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13799375#comment-13799375
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oli mcc edited comment on LUCENE-4978 at 10/18/13 6:30 PM:
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Hi David,
Sorry for the delay in following up, I've actually been spending some time
familiarizing myself with the code and have some followup thoughts/questions.
I think I get the issue now; the optimization short circuits to using the
centre (a cheaper relation verification) in some cases, and as a result, the
following two query types (a point and polygon) would not match due to no
intersection with the centre.
!https://docs.google.com/drawings/d/1iEX4D7PXQHq3mJvSII-Y0Y5MHPKSGOkqjUV6UcIecY4/pub?w=759&h=353!
- It's not clear to me why the quick fix doesn't work in both cases you
described however, maybe I'm missing the underlying problem. If we _always_
use cell.getShape() won't we be guaranteed to match all points in the cell
(potentially inefficient and with false positives, but not false negatives)?
- I think this is purely a query time issue, would that be right? I'd like to
start indexing documents now, but will avoid doing so if a fix to this will
require a re-index.
To hopefully answer your question, Elasticsearch does have a specific mapping
type for geo points
([GeoPointFieldMapper.java|https://github.com/elasticsearch/elasticsearch/blob/master/src/main/java/org/elasticsearch/index/mapper/geo/GeoPointFieldMapper.java]
which I think follows the pattern you described.
was (Author: olimcc):
Hi David,
Sorry for the delay in following up, I've actually been spending some time
familiarizing myself with the code and have some followup thoughts/questions.
I think I get the issue now; the optimization short circuits to using the
centre (a cheaper relation verification) in some cases, and as a result, the
following two query types (a point and polygon) would not match due to no
intersection with the centre.
!https://docs.google.com/drawings/d/1iEX4D7PXQHq3mJvSII-Y0Y5MHPKSGOkqjUV6UcIecY4/pub?w=759&h=353!
- It's not clear to me why the quick fix doesn't work in both cases you
described however, maybe I'm missing the underlying problem. If we _always_
use cell.getShape() won't we be guaranteed to match all points in the cell
(potentially inefficient and with false positives, but not false negatives)?
- I think this is purely a query time issue, would that be right? I'd like to
start indexing documents now, but will avoid doing so if a fix to this will
require a re-index.
To answer your question, Elasticsearch does have a specific mapping type for
geo points
([GeoPointFieldMapper.java|https://github.com/elasticsearch/elasticsearch/blob/master/src/main/java/org/elasticsearch/index/mapper/geo/GeoPointFieldMapper.java]
which I think follows the pattern you described.
> Spatial search with point query won't find identical indexed point
> ------------------------------------------------------------------
>
> Key: LUCENE-4978
> URL: https://issues.apache.org/jira/browse/LUCENE-4978
> Project: Lucene - Core
> Issue Type: Bug
> Components: modules/spatial
> Affects Versions: 4.1
> Reporter: David Smiley
> Assignee: David Smiley
> Priority: Minor
> Fix For: 4.6
>
>
> Given a document with indexed POINT (10 20), when a search for INTERSECTS(
> POINT (10 20)) is issued, no results are returned.
> The work-around is to not search with a point shape, use a very small-radius
> circle or rectangle. (I'm marking this issue as "minor" because it's easy to
> do this).
> An unstated objective of the PrefixTree/grid approximation is that no matter
> what precision you use, an intersects query will find all true-positives.
> Due to approximations, it may also find some close false-positives. But in
> the case above, that unstated promise is violated. But it can also happen
> for query shapes other than points which do in fact barely enclose the point
> given at index time yet the indexed point is in-effect shifted to the center
> point of a cell which could be outside the query shape, and ultimately
> leading to a false-negative.
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