[Qgis-user] inconsistenty when calculating area depending on file type or projection?

[Carlos Cerdán]

> Under project properties, general tab - change "ellipsoid" to "None
/Planimetric".

Done, but calculated area is still... geodetic area?. I've tried ArcGIS
and, for my GEO layer, It gives me desired area (same as an UTM layer,
calculated with OTF off); so, it's me or QGIS, but I can't do this task in
one step on QGIS: first I've to reproject mi GEO layer into an UTM one;
disable OTF and finally calculate area (planar, as UTM is) in the new UTM
layer.


Carlos🤔




2016-10-18 19:58 GMT-05:00 Nyall Dawson <nyall.dawson at gmail.com>:

> On 19 October 2016 at 02:22, Carlos Cerdán <sig.upagu at gmail.com> wrote:
> > It was my fault. I was used to consider plane areas as "correct",
> forgetting
> > ellipsoidal areas. So, QGIS give us freedom to calculate planar or
> > ellipsoidal (geodetical) areas, but we must be careful about settings; Is
> > not it?. Sometimes, too much freedom is annoying!
> >
> > But, How can I calculate UTM (planar) area from a GEO layer in one step?
>
> Under project properties, general tab - change "ellipsoid" to "None /
> Planimetric".
>
> I keep meaning to split up the concept of ellipsoidal measurement from
> OTF reprojection. In my view these are two different concepts - one is
> just about display of data, the other relates to measurement. Ie, you
> should be able to perform ellipsoidal calculations even if OTF
> rendering is disabled.
>
> I just keep forgetting to do it early in a release cycle for extensive
> testing...
>
> Nyall
>
>
>
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