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https://issues.apache.org/jira/browse/SOLR-2155?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13114686#comment-13114686
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geert-jan brits edited comment on SOLR-2155 at 9/26/11 2:16 PM:
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David, to clarify:
My use-case could be either represented as:
1. a bag of points, in which case I want to be able to return the closest
point to a user-defined point and sort on the distance
2. a polygon made of the points (where the points are the vertices of the
polygon) and return the closest distance from a user-defined point to the
polygon.
Either of the solutions suffices for me, from your answer I can't entirely see
if that was clear.
You mention: "Sorting by (multi-value) indexed shapes is supported only for
points".
Does this mean that representation 1.) above is supported? It wasn't entirely
clear for me from your response.
Let me give you the use-case, (and why the sort on center-point / centroid is
not going to work):
Consider a travel application in which walks/itineraries can be defined. Most
of the walks are defined as roundtrips (i.e: beginpoint = endpoint). In my
representation (for now) a walk visits certain Points of interest (poi) (which
each have a lat/long point defined) in a certain order.
A lot of walks can be started at any given Poi. (bc. of the roundtrip nature).
I want a user to be able to request walks that are nearby. (sorted based on
distance). For each walk the distance becomes the closest Poi (thus point)
defined in the walk related to the user-defined point.
Does this make sense?
P.s: having only though of representing this problem as polygons to support the
'find closest point'-query, I skimmed over the fact that for my notion of a
walk (ordered collection of points) , connecting the points in the order
specified may generate a complex (self-intersecting) polygon. Are these
polygons supported in the LSP?
was (Author: gbrits):
David, to clarify:
My use-case could be either represented as:
1. a bag of points, in which case I want to be able to return the closest
point to a user-defined point and sort on the distance
2. a polygon made of the points (where the points are the vertices of the
polygon) and return the closest distance from a user-defined point to the
polygon.
Either of the solutions suffices for me, from your answer I can't entirely see
if that was clear.
You mention: "Sorting by (multi-value) indexed shapes is supported only for
points".
Does this mean that representation 1.) above is supported? It wasn't entirely
clear for me from your response.
Let me give you the use-case, (and why the sort on center-point / centroid is
not going to work):
Consider a travel application in which walks/itineraries can be defined. Most
of the walks are defined as roundtrips (i.e: beginpoint = endpoint). In my
representation (for now) a walk visits certain Points of interest (poi) (which
each have a lat/long point defined) in a certain order.
A lot of walks can be started at any given Poi. (bc. of the roundtrip nature).
I want a user to be able to request walks that are nearby. (sorted based on
distance). For each walk the distance becomes the closest Poi (thus point)
defined in the walk related to the user-defined point.
Does this make sense?
> 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
> Assignee: Grant Ingersoll
> Attachments: GeoHashPrefixFilter.patch, GeoHashPrefixFilter.patch,
> GeoHashPrefixFilter.patch,
> SOLR-2155_GeoHashPrefixFilter_with_sorting_no_poly.patch, SOLR.2155.p3.patch,
> SOLR.2155.p3tests.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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