[QGIS-Developer] [Qgis-user] New Features in Shape Tools 3.2.0

[Kristian Evers]

A possible explanation could be that QGIS doesn't pick up the correct ellipsoid definition from the CRS metadata. I had a hunch that might be the problem but couldn’t come up with a test to confirm it. I suspect it would be simple to test in debug mode. 

/Kristian

-----Oprindelig meddelelse-----
Fra: QGIS-Developer <qgis-developer-bounces at lists.osgeo.org> På vegne af Nyall Dawson
Sendt: 27. september 2018 08:32
Til: hellik at web.de
Cc: qgis-developer <qgis-developer at lists.osgeo.org>
Emne: Re: [QGIS-Developer] [Qgis-user] New Features in Shape Tools 3.2.0

On Wed, 26 Sep 2018 at 03:52, Helmut Kudrnovsky <hellik at web.de> wrote:
>
> >[...]
> >Caris LOTS: 14.737 km^2
> >ArcMap:     14.727,446 km^2
> >MapInfo:    14.727,352 km^2
> >GeoMedia:   14.726,443 km^2
> >Planimeter: 14.722,522 km^2
> >QGIS 3.2:   14.652,181 km^2
> >QGIS 2.8:   14.652,181 km^2
> >[...]
> >My suspicion is that the geodesic algorithm used by QGIS (and apparently
> GRASS) is to blame here.
>
> a quick check in GRASS 7.7.svn shows :-)
>
> |m2|km2|
> |14718097678,673|14.718,097679|

Hmm... confusing. I've double checked and the QGIS/GRASS code matches,
so we should get identical results. The cause must lie in the data
passed to the area calculation. I'll investigate.

Nyall
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