Dear Nyall, Thank you so much for analyzing the issue and also thank you in advance for porting the fix to 2.18!
I opened the sample project with 2.14 and I can confirm that the area values of both planimetric and ellipsoidic area calculations are very close for all features. It is very much appreciated! Thanks, Andreas On 2017-02-03 01:36, Nyall Dawson wrote: > On 1 February 2017 at 19:55, Neumann, Andreas <a.neum...@carto.net> wrote: > >> Hi Nyall, >> >> Thanks for the explanations. I should have read the explanations of the help >> text more closely. It explains it all. >> >> However, there still seem to be issues. Consider the following results >> below. First column is the result of $area, second column is area($geometry). >> >> Sometimes the results are very close, in other cases the difference is >> massive. Like in the very first row. 32'087 vs 190'605'589 square meters. >> This can't be explained with ellipsoidical vs. planimetric. In this first >> row, the result of area($geometry) (planimetric) seems correct, while the >> ellipsoidical result ($area) is massively wrong. >> >> How can this huge difference be explained? > > Ok - I've looked into this. It's not an issue in 2.14 or 3.0, just 2.18. > > It was most likely fixed by: > https://github.com/qgis/QGIS/commit/abc0919 "Fix area calculation of > compoundcurve rings if they contain a 2-vertex linestring" > > Committed to 2.14 (with unit tests), I forward ported to 3.0, but it > hasn't been applied to 2.18. I'll do this. > > Nyall
_______________________________________________ Qgis-developer mailing list Qgis-developer@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer
