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From <Ankit.Mura...@ril.com>
Subject RE: Distance between 2 points Lucene Spatial
Date Mon, 22 Dec 2014 14:35:19 GMT
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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