I would not be in favour of supporting a many geometry type per layer type setup, it just makes things a heap more complicated IMO for little gain.
Also makes your code a lot more complicated, you now have to check each geometry for type because you are never sure what you will get. MapInfo did this and it was more a pain then a feature. On Thu, 2 Apr 2015 10:11 pm Denis Rouzaud <denis.rouz...@gmail.com> wrote: > Hi Olivier, > > I think you can easily extend your reasoning to the support of multiple > geometry columns in QGIS. > I believe that this would come in QGIS at some point. > > If QGIS 3 is getting closer, our company will support this feature. > > As you suggest, the layer could have different geometry types and/or > columns. This could be seen as sub-layer level for rendering: > layer > geometry types/columns > symbology rules > > I suppose this is quite a big change. Many things depends on the geometry > type in QGIS (like map map tools), and that would represent a large API > break. > > But, on my side, I believe it's a logic evolution for QGIS. > > Best wishes, > > Denis > > > > > > > On 04/02/2015 01:52 PM, Olivier Dalang wrote: > > Hi, > > In some projects of mine, I work with multiple geometry types in one > postgis table, using a column of type geometry(Geometry,4326). > This is very well supported by postgis. > > It is possible to load such a table in QGIS by manually selecting the > geometry type you want to load. This means that to display all the > features, you need to add the table three times, one for each feature type. > > This works more or less. There are a few bugs though : > - http://hub.qgis.org/issues/12499 (you can edit other type's node with > the node tool) > - http://hub.qgis.org/issues/12500 (other type's records are shown in the > attribute table) > > This also has some limitations. When having such a setup, it's pretty > sure you'll want to have the same edit forms for all the layers. You'll > also probably want the same filter, the same labels, the same actions, > etc... > The only thing you'd want to be able to define on a geometry type basis > are the symbol (well, even the classification/colors/etc could be shared) > and the label placement. > For now, you must do all settings three times, because of this bug/feature > request : > - http://hub.qgis.org/issues/12303 (copy/paste style from one geometry > type to another) > > > As you see, support multiple geometry types in QGIS is not perfect. > > Of course it's possible to fix the bugs/pr, and there are some > workarounds (postgis view instead of tables) but maybe it's also worth > thinking a bit more in depth about this. > > We could consider point/line/polygons as subcategories/sublayers of a > layer. A shapefile or a mono-typed table would have only one of those > sublayer, but a postgis table could perfectly have the three. Most of the > settings would be defined at the layer level, while only some settings > would be defined at the subcategory level. > > This is probably especially relevant when thinking long term (the day we > support 3D, curves, etc...). > > > What do you think ? > Do you think the relation 1 layer = 1 geometry type will hold ? > > I think we inherited this from the old shapefile format, but most data > sources QGIS handles don't have this limitation. I also think it does not > hold with quite a lot of modern GIS uses (especially web related, think of > openstreetmaps for instance). > > There's this feature request (6th oldest open issue on the tracker) > about postgis geometry collections : http://hub.qgis.org/issues/167 > > > Best, > > Olivier > > > > > > _______________________________________________ > Qgis-developer mailing > listQgis-developer@lists.osgeo.orghttp://lists.osgeo.org/mailman/listinfo/qgis-developer > > > > > > _______________________________________________ > Qgis-developer mailing list > Qgis-developer@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/qgis-developer
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