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https://issues.apache.org/jira/browse/SOLR-2155?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12920554#action_12920554
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Robert Muir commented on SOLR-2155:
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{quote}
One area that I know nothing about is how scoring/sorting actually works within
Lucene. For the work here I wasn't in need of that but many people clearly want
that. In your opinion Rob, is there any opportunity for geo sorting/relevancy
code to take advantage of any efficiencies done here or are they completely
unrelated?
{quote}
Thats a good question, I'm not sure this stuff will help with that. But there
is also a lot of people who like you, don't need/want to integrate it into
scoring and maybe just want to filter on distance really fast, and score based
on something else.
I'm not a spatial guy and don't understand the spatial goings-on, but it seems
like maybe people who want to do relevance based on distance could achieve that
some other way and use the trie value to just have a really fast bounding "box"
filter.
maybe they use a solr function query or however this is done but the filter
would speed it up tremendously, of course with some loss of precision, but this
is search, its not like the textual component has perfect precision, and a lot
of people arent going across meridians or the earth's poles or anything.
> 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
>
>
> 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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