yes, that would generate/utilize a local Spatialite DB or Python RTree “working area” , could be quite powerful, especially if somehow exposed as Python objects, and/or integrated with the Processing framework …
Chris > On Sat, Feb 18, 2017 at 8:41 PM, Anita Graser <anitagraser at gmx.at > <https://lists.osgeo.org/mailman/listinfo/qgis-developer>> wrote: > >> Hi, >> >> I'm looking for a better way to handle stationary objects in Time >> Manager. >> For example, think of a real estate map, where plots of land change value >> over time. The geometries themselves rarely ever change. >> >> Currently. It is necessary to create a join of plot geometries and values >> over time, duplicating geometries and creating potentially huge layers. >> >> So far, my thoughts are going in the direction of creating query layers >> for such cases. The query layer definition could be controlled by Time >> Manager, to always update according to the requested time frame. >> >> Does that sound reasonable? Do you have other ideas or are there any >> plans about adding temporal support to QGIS3 that I should be aware of? >> > > > Experiments so far (with 2.18) have turned up that virtual layers don't > seem to support getProvider().minimumValue() > which makes them unusable in Time Manger. > That is minimumValue() and uniqueValues() seem to always just return None. Best wishes, Anita
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