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https://issues.apache.org/jira/browse/SOLR-2155?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12989534#comment-12989534
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Bill Bell commented on SOLR-2155:
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OK. A couple things. If we know which lat,long was used for the result, that
could be used for the geodist(). There seems to be an issue when you use
geodist($pt,$sfield) when $sfield is a geohash.
The most important is the sort parameter. It is easy enough to calculate the
distance.
sort=geodist($pt, $sfield)+asc needs to work. For example...
data for a document has:
score=45.15,-100.85
score=45.15,-93.85
1. If we switch the pt=45,-93.1, it should use distance to 45.15,-93.85 in the
sort by geodist()
2. If we switch the pt=45.15,-100.1, it should use distance to 45.15,-100.85 in
the sort by geodist()
You could do this by changing geodist() to work with geohash to find closest
and return the distance from the list.
> Geospatial search using geohash prefixes
> ----------------------------------------
>
> Key: SOLR-2155
> URL: https://issues.apache.org/jira/browse/SOLR-2155
> Project: Solr
> Issue Type: Improvement
> Reporter: David Smiley
> Attachments: GeoHashPrefixFilter.patch, GeoHashPrefixFilter.patch,
> GeoHashPrefixFilter.patch
>
>
> There currently isn't a solution in Solr for doing geospatial filtering on
> documents that have a variable number of points. This scenario occurs when
> there is location extraction (i.e. via a "gazateer") occurring on free text.
> None, one, or many geospatial locations might be extracted from any given
> document and users want to limit their search results to those occurring in a
> user-specified area.
> I've implemented this by furthering the GeoHash based work in Lucene/Solr
> with a geohash prefix based filter. A geohash refers to a lat-lon box on the
> earth. Each successive character added further subdivides the box into a 4x8
> (or 8x4 depending on the even/odd length of the geohash) grid. The first
> step in this scheme is figuring out which geohash grid squares cover the
> user's search query. I've added various extra methods to GeoHashUtils (and
> added tests) to assist in this purpose. The next step is an actual Lucene
> Filter, GeoHashPrefixFilter, that uses these geohash prefixes in
> TermsEnum.seek() to skip to relevant grid squares in the index. Once a
> matching geohash grid is found, the points therein are compared against the
> user's query to see if it matches. I created an abstraction GeoShape
> extended by subclasses named PointDistance... and CartesianBox.... to support
> different queried shapes so that the filter need not care about these details.
> This work was presented at LuceneRevolution in Boston on October 8th.
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