Re: [Qgis-developer] Hierarchy of new geometry classes
http://osgeo-org.1560.x6.nabble.com/Questions-regarding-new-geometry-engine-td5208770.html#a5209162 On 23.06.2015 05:58, Martin Dobias wrote: Hi Recently I have been looking a bit at the new geometry classes and there is one thing I do not understand: if QgsLineStringV2 is derived from QgsCurveV2 and QgsPolygonV2 is derived from QgsSurfaceV2, why is not the same approach used for multi-part geometries? Currently QgsMultiLineStringV2 and QgsMultiPolygonV2 are subclasses of QgsGeometryCollectionV2 - but why they are not derived from QgsMultiCurveV2 and QgsMultiSurfaceV2 respectively? It looks like OGR uses that approach too (multi-polygon from multi-surface and multi-linestring from multi-curve): http://www.gdal.org/classOGRGeometry.html Regards Martin ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer -- Dr. Marco Hugentobler Sourcepole - Linux Open Source Solutions Weberstrasse 5, CH-8004 Zürich, Switzerland marco.hugentob...@sourcepole.ch http://www.sourcepole.ch Technical Advisor QGIS Project Steering Committee ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] Hierarchy of new geometry classes
Hi Marco On Tue, Jun 23, 2015 at 2:27 PM, Marco Hugentobler marco.hugentob...@sourcepole.ch wrote: http://osgeo-org.1560.x6.nabble.com/Questions-regarding-new-geometry-engine-td5208770.html#a5209162 Thanks - I thought this was already asked, but couldn't find where... IMO the hierarchy in QGIS should follow the one in ISO and OGC models. Maybe right now there is no practical advantage for the implementation to follow the hierarchy, but is there a strong reason to deviate from it? It seems confusing that multi-polygon cannot be cast to multi-surface. I am afraid that things like this can bite us later... Regards Martin ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] Hierarchy of new geometry classes
Hi Martin but is there a strong reason to deviate from it? Only a week reason ( clone() method ). But I think you are right and it might be better to follow the ISO model to be more compatible with other libs. Regards, Marco On 23.06.2015 08:39, Martin Dobias wrote: Hi Marco On Tue, Jun 23, 2015 at 2:27 PM, Marco Hugentobler marco.hugentob...@sourcepole.ch wrote: http://osgeo-org.1560.x6.nabble.com/Questions-regarding-new-geometry-engine-td5208770.html#a5209162 Thanks - I thought this was already asked, but couldn't find where... IMO the hierarchy in QGIS should follow the one in ISO and OGC models. Maybe right now there is no practical advantage for the implementation to follow the hierarchy, but is there a strong reason to deviate from it? It seems confusing that multi-polygon cannot be cast to multi-surface. I am afraid that things like this can bite us later... Regards Martin -- Dr. Marco Hugentobler Sourcepole - Linux Open Source Solutions Weberstrasse 5, CH-8004 Zürich, Switzerland marco.hugentob...@sourcepole.ch http://www.sourcepole.ch Technical Advisor QGIS Project Steering Committee ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
