I think we should normalize the list to avoid duplicated ellipsoids, which is misleading to the user.
I guess multiple issues are crossing. 1 - problems with the ellipsoid definition causing wrong measurements 2 - problems with the list making the combo box not behaving correctly (select WGS84 but Clark 1866 appears when reopening peoject properties) giovanni Il 21 ott 2017 20:47, "Régis Haubourg" <[email protected]> ha scritto: > Hi Nyall, a partial answer maybe. > IGNF is a registry from French National Geographic Institute. They have > brought their own registry into proj4, which is perfectly valid an > authorized, but obviously creates confusions for the same SRS available in > the EPSG registry. Moreove, most definitions are identical, except that the > IGNF adds a nad grid for a better precision. > From what I see in the issue, some non IGNF definition also causes > trouble, when a and b parameter are set to zero. I think that this is more > a QGIS (or proj4?) issue than a problem with the projection list. > I would really like to know too when and how are the srs lists loaded in > QGIS. > > Cheers > Régis > > 2017-10-21 2:10 GMT+02:00 Nyall Dawson <[email protected]>: > >> On 19 October 2017 at 19:01, G. Allegri <[email protected]> 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 >> _______________________________________________ >> QGIS-Developer mailing list >> [email protected] >> List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer >> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer > > >
_______________________________________________ QGIS-Developer mailing list [email protected] List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer
