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From "David Smiley (JIRA)" <>
Subject [jira] [Commented] (LUCENE-7158) Haversin should use the earth's mean radius, not its max (equitorial)?
Date Fri, 01 Apr 2016 04:00:28 GMT


David Smiley commented on LUCENE-7158:

+1.  I especially like the URL reference to
-- it's important to track where our reference data and lifted algorithms come from.
What do you mean be "restapled"?

> Haversin should use the earth's mean radius, not its max (equitorial)?
> ----------------------------------------------------------------------
>                 Key: LUCENE-7158
>                 URL:
>             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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