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From "david.w.smiley@gmail.com" <david.w.smi...@gmail.com>
Subject Re: Distance between 2 points Lucene Spatial
Date Mon, 22 Dec 2014 15:09:25 GMT
I forgot this part of your question.

To go from degrees to KM, multiply by DistanceUtils.DEG_TO_KM.

~ David Smiley
Freelance Apache Lucene/Solr Search Consultant/Developer
http://www.linkedin.com/in/davidwsmiley

On Mon, Dec 22, 2014 at 9:35 AM, <Ankit.Murarka@ril.com> wrote:
>
> Thanks for the suggestion.
>
> I am using Lucene Vincenty to find the distance but the output is strange.
> I cannot figure out how to convert the output to metres/kilo metres.
>
> After extensive search on google, I found GeoDesy source code which gives
> me distance in metres. This is also the implementation of Vincenty.
>
> However, I do not intend to use GeoDesy.
>
>  I would prefer to use inbuilt Vincenty of Lucene to get the distance in
> metres but I am unable to find this.
>
> Please suggest.
>
>
> -----Original Message-----
> From: david.w.smiley@gmail.com [mailto:david.w.smiley@gmail.com]
> Sent: 22 December 2014 19:33
> To: java-user@lucene.apache.org
> Subject: Re: Distance between 2 points Lucene Spatial
>
> Hi Ankit,
>
> Vincenty is the most accurate one — it is the benchmark for the other 2’s
> tests for the true answer.  In theory it produces the same answers as the
> other 2 simpler formulas you mention but is “numerically robust” for
> computers.  Note that the world model used by Spatial4j when in “geo” mode
> is a spherical model.  For more accurate distance computation on Earth, use
> an ellipsoidal model.  If you google “Vincenty”, it's easy to find
> Vincenty’s ellipsoidal formula with the constants for Earth; that is most
> often what he is associated with.
>
> ~ David Smiley
> Freelance Apache Lucene/Solr Search Consultant/Developer
> http://www.linkedin.com/in/davidwsmiley
>
> On Mon, Dec 22, 2014 at 12:35 AM, <Ankit.Murarka@ril.com> wrote:
> >
> > Dear All,
> >
> > We are using lucene spatial strategy to find out the distance between
> > a pair of Lat/Long.
> >
> > Given a pair of Lat/Long I need to find the near accurate distance
> > between these 2 points.
> >
> > I have used Haversine, LawOfCosines and Vincernity however unable to
> > decide which will provide the best output(accurate output).
> >
> > There is not just 1 point but millions of points which will need to be
> > passed into against  a set of point to find the closest point.
> >
> > Which might be the best approach. Additionally, I observed from the
> > API, that the output of these 3 algorithms are in Degress. Is there
> > any API in lucene which can return the output in double,long,int etc.
> formats.
> >
> >
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