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From "ASF subversion and git services (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (LUCENE-7158) Haversin should use the earth's mean radius, not its max (equitorial)?
Date Fri, 01 Apr 2016 09:39:25 GMT

    [ https://issues.apache.org/jira/browse/LUCENE-7158?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15221457#comment-15221457
] 

ASF subversion and git services commented on LUCENE-7158:
---------------------------------------------------------

Commit cf7967cc467d9d697d520fcdf92fcdb52f7ddd4e in lucene-solr's branch refs/heads/master
from Mike McCandless
[ https://git-wip-us.apache.org/repos/asf?p=lucene-solr.git;h=cf7967c ]

LUCENE-7158: use the same value (from WGS84) for earth's mean radius when we approximate it
as a sphere


> Haversin should use the earth's mean radius, not its max (equitorial)?
> ----------------------------------------------------------------------
>
>                 Key: LUCENE-7158
>                 URL: https://issues.apache.org/jira/browse/LUCENE-7158
>             Project: Lucene - Core
>          Issue Type: Improvement
>            Reporter: Michael McCandless
>         Attachments: LUCENE-7158.patch, LUCENE-7158.patch
>
>
> Across our spatial modules we seem to disagree about the earth's radius when we model
it as a sphere.
> I think in our haversin implementation we use equitorial (maximum) radius, but maybe
in spatial3d we use the earth's mean radius.
> I think mean makes more sense: the earth is actually a squashed sphere, so it's polar
radius is shorter than its equitorial radius.
> I think it's important, when we model the earth as a sphere, that we pick one radius
and try to use that one consistently?



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