[QGIS-Developer] problems with IGNF:ELG ellipsoids in srs.db

[Nyall Dawson]

On 19 October 2017 at 19:01, G. Allegri <giohappy at gmail.com> wrote:
> Some measurement testing on QGIS 3.0 revealed that
> https://issues.qgis.org/issues/13957 issue is still there, and it's quite
> subtle because we have very similar elliposid names, with similar
> definitions except IGNF:ELG ones have trailing zeros.
>
> For example WGS84:
>
> id     acronym            name      radius                     parameter2
> --------------------------------------------------------------------------------------------------
> 41 WGS84             WGS 84  a=6378137.0          rf=298.257223563
> 51 IGNF:ELG053   WGS84   a=6378137.0000    rf=298.2572235630000
>
> This is quite misleading for the user whene selecting the elliposid for
> Measurements.
> Anyway, it could be accepted if they both worked but in case ellispoid #51
> is selected two problems appear:
>
> 1 - the selected ellipsoid is not retained in the dropdown box. If you
> reopen project properties "Clarke 1866" is selected instead of "WGS84"
> 2 - (maybe related to the latter) measure values are completely wrong
>
> Everything works fine if "WGS 84" (ellipsoid #41) is selected.

I'm also curious about this  -  has anyone got any background on how
the ellipsoid list has been generated and the rationale behind these
inclusions?

Nyall