[Proj] degree to radian conversions
Even Rouault
even.rouault at spatialys.com
Thu Aug 13 13:58:36 PDT 2015
Le jeudi 13 août 2015 22:46:03, Charles Karney a écrit :
> I just submitted a pull request for proj.4 to correct the values of the
> constants used in degree/radian conversions. The important change was
> to use
>
> .0174532925199432958
>
> instead of
>
> .0174532925199433
>
> as the value of pi/180 used to convert degrees to radians in dmstor.c.
> The new value is substantial closer to the true value...
>
> cos(90 * .0174532925199432958) = 6.1e-17
> cos(90 * .0174532925199433) = -3.8e-16
>
> Needless to say, some of the tests now fail. Particularly because
> proj.4 used to round 90 deg to an illegal latitude (larger than pi/2).
>
> However the changes for the healpix checks are inexplicably large.
>
> It would be good if someone could figure out why the healpix results
> change so much.
Adding in CC the authors mentionned in PJ_healpix.c, if they're not subscribed
to this mailing list, in case they have an idea.
And for everyone, the commit of the pull request :
https://github.com/OSGeo/proj.4/commit/794052ed09f5c9e4ee49ece4af7f641098e29eb4
And test failures:
https://travis-ci.org/OSGeo/proj.4/jobs/75476366
Even
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