Not at all. The change has already been committed to the development version.
giovanni 2012/4/6 blavet <[email protected]> > ** > Thank you very much for this very fast and efficient diagnosis > > Best regards > > Didier Blavet > > Le 06/04/2012 12:01, G. Allegri a écrit : > > Probably I've found the bug. > In Qgis the semi-minor axis of the ellipsoid is calculated with: > > b = a - (f/a) > > where > b = semi-minor axis > a = semi-majot axis > f = inverse flattening > > while it should be: > > b = a - (a/f) > > > In Qgis the WGS84 semi-minor axis is 6378136,xxx > while it should be 6356752.xxx > > giovanni > > > > > > 2012/4/6 G. Allegri <[email protected]> > >> AFAICS, the Qgis formula [1] to calculate distances on ellipssoid is >> Vincenty's. >> I've reproduced it for the first set of points and I can confirm tha QGis >> gives 540.9973919726176 m >> >> The online Vincenty calculator [2] gives 540.045 m >> >> I suppose it's a rounding issue. >> I will investigate it more... >> >> giovanni >> >> >> [1] >> http://trac.osgeo.org/qgis/browser/trunk/qgis/src/core/qgsdistancearea.cpp#L540 >> >> [2] http://www.movable-type.co.uk/scripts/latlong-vincenty.html >> >> 2012/4/6 blavet <[email protected]> >> >>> Dear QGis Developpers and Users >>> >>> >>> >>> _______________________________________________________________________________________ >>> >>> *Didier B**lavet* >>> >>> Institut de Recherche pour le Développement - IRD (http://www.ird.fr) >>> >>> UMR Eco&Sols - Ecologie Fonctionnelle & Biogéochimie des Sols & >>> Agroécosystèmes >>> >>> (Montpellier SupAgro-CIRAD-INRA-IRD) ( >>> http://www.montpellier.inra.fr/ecosols) >>> >>> Bâtiment 12, 2 place Viala, F-34060 Montpellier Cedex 2 , France >>> >>> Tel bureau : +33 (0)4 99 61 21 33 >>> >>> Secrétariat : +33 (0)4 99 61 21 01 / Fax : +33 (0)4 99 61 21 19 >>> >>> Courriel : [email protected] >>> >>> >>> _______________________________________________________________________________________ >>> >>> _______________________________________________ >>> Qgis-user mailing list >>> [email protected] >>> http://lists.osgeo.org/mailman/listinfo/qgis-user >>> >>> >> > > -- > > > _______________________________________________________________________________________ > > *Didier B**lavet* > > Institut de Recherche pour le Développement - IRD (http://www.ird.fr) > > UMR Eco&Sols - Ecologie Fonctionnelle & Biogéochimie des Sols & > Agroécosystèmes > > (Montpellier SupAgro-CIRAD-INRA-IRD) ( > http://www.montpellier.inra.fr/ecosols) > > Bâtiment 12, 2 place Viala, F-34060 Montpellier Cedex 2 , France > > Tel bureau : +33 (0)4 99 61 21 33 > > Secrétariat : +33 (0)4 99 61 21 01 / Fax : +33 (0)4 99 61 21 19 > > Courriel : [email protected] > > > _______________________________________________________________________________________ >
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