[Qgis-developer] stationary objects over time

[Chris Nicholas]

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

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/qgis-developer/attachments/20170224/13330e01/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 842 bytes
Desc: Message signed with OpenPGP using GPGMail
URL: <http://lists.osgeo.org/pipermail/qgis-developer/attachments/20170224/13330e01/attachment.sig>