dr wrote > So I would say it seems like an error in the area calculation algorithm in > QGIS.
Hi, there is no unique way to calculate the geodesic area. For example, PROJ use a C implementation of the GeographicLib algorithm, while QGIS uses the same algorithm used by GRASS, SpatiaLite 5 uses RTTOPO library and PostGIS uses GeographicLib. See this recent threed http://osgeo-org.1560.x6.nabble.com/Confusion-with-ellipsoidal-method-of-area-td5454013.html on the same topic. There are two feature requests for QGIS and GRASS: https://github.com/qgis/QGIS/issues/40888 https://github.com/OSGeo/grass/issues/1235 and a Pull Request in GRASS https://github.com/OSGeo/grass/pull/1283. So it look like there is the possibility that GRASS will switch to use the same C implementation of the GeographicLib algorithm used by PROJ. Regards. Andrea -- Sent from: http://osgeo-org.1560.x6.nabble.com/QGIS-Developer-f4099106.html _______________________________________________ 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