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Posted to dev@lucene.apache.org by "Lance Norskog (JIRA)" <ji...@apache.org> on 2010/12/07 04:09:09 UTC

[jira] Issue Comment Edited: (SOLR-2268) Add support for Point in Polygon searches

    [ https://issues.apache.org/jira/browse/SOLR-2268?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12968553#action_12968553 ] 

Lance Norskog edited comment on SOLR-2268 at 12/6/10 10:08 PM:
---------------------------------------------------------------

1 trick for speeding up "document holds polygons", using vertex-based hashing of lat/long values. (It's a variation on a kind of bitwise filtering whose name I cannot remember: if the bit is off, there is no match, but if the bit is on there may be a match.)

Master data: A field with one or more polygon descriptions.
Bitwise data: Two bit fields, latitude&longitude, with a string of bits for each vertex. For example, given a Level Of Detail (LOD) of 1 degree, there would be 360 bits in either bitfield. The document would have one of each bitfield. Each degree's bit is true if any polygon has area within that bit's degree. 

The first phase of searching for point in all polygons is to check the latitude and longitude bitfields for that point.

      was (Author: lancenorskog):
    2 tricks for speeding up "document holds polygons", using vertex-based hashing of lat/long values. (It's a variation on a kind of bitwise filtering whose name I cannot remember: if the bit is off, there is no match, but if the bit is on there may be a match.)

Master data: A field with one or more polygon descriptions.
Bitwise data: Two bit fields, latitude&longitude, with a string of bits for each vertex. For example, given a Level Of Detail (LOD) of 1 degree, there would be 360 bits in either bitfield. The document would have one of each bitfield. Each degree's bit is true if any polygon has area within that bit's degree. 

The first phase of searching for point in all polygons is to check the latitude and longitude bitfields for that point.
  
> Add support for Point in Polygon searches
> -----------------------------------------
>
>                 Key: SOLR-2268
>                 URL: https://issues.apache.org/jira/browse/SOLR-2268
>             Project: Solr
>          Issue Type: New Feature
>            Reporter: Grant Ingersoll
>            Assignee: Grant Ingersoll
>
> In spatial applications, it is common to ask whether a point is inside of a polygon.  Solr could support two forms of this: 
> # A field contains a polygon and the user supplies a point.  If it does, the doc is returned.  
> # A document contains a point and the user supplies a polygon.  If the point is in the polygon, return the document
> With both of these case, it would be good to support the negative assertion, too.

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