[QGIS-Developer] Model for Temporal Measurement (vector) Datasets ?

[Matthias Kuhn]

Hi Richard,

It seems to me this should be possible using:

1. Two tables:
- Points
- Measurements (Timestamp, Measured attribute)

2.  A view (Points LEFT JOIN Measurements)

Timescale as proposed by Tim can be added to the mix to optimize things if
you have additional requirements for time-specific aggregates or optimized
storage.

Matthias

On Sun, Sep 4, 2022 at 3:18 PM Richard Duivenvoorde via QGIS-Developer <
qgis-developer at lists.osgeo.org> wrote:

> On 9/4/22 14:35, Tim Sutton wrote:
> > Hi Richard
> >
> > Don’t people normally use things like https://www.timescale.com/ <
> https://www.timescale.com/?utm_source=timescaledb-paid&utm_medium=google-search&utm_campaign=brand-2022&utm_content=homepage&utm_term=timescale-postgres&gclid=EAIaIQobChMIspXn6JL7-QIVOpBoCR3QLQf8EAAYASAAEgL09PD_BwE
> >
> >
> > For this? In any case some of our clients that are doing things like
> vehicle tracking are…
>
> Yes to *store* it, but my point is: given 2 points with 100 timesteps,
> QGIS will create 200 features for it to be able to display it...
> So to 'view' that data in (Q)GIS, you have to flatten it to a 'table' with
> 200 features...
>
> While the actual interesting part is the value and the time, NOT those 2
> xy fields... (the case of moving vehicles is slightly different, there the
> xy values also change)...
> Maybe I'm in the wrong crowd here to tell the geoms are not so much of
> interest in my case ;-)
>
> I'm looking for a way/model (non tabular) that QGIS creates 2
> geometries/features, and then will style/paint it based on the timestamps
> and values
>
> The use case here: having 5000 sensors in Europe, having 500.000.000
> measurements in total, I don not want to create 500.000.000 features.
>
> I'd preferred to create those 5000 features, and then get the
> geom-id/value/timestamp for a given filter range and repaint my canvas.
>
> Something like 'dynamic' joins: the geometries will stay the same, but the
> 'joined' columns/table will change based on the 'temporal filter' requested.
>
> Sorry if I can not make myself more clear (or making it more complex that
> it maybe is...) :-)
>
> Regards,
>
> Richard Duivenvoorde
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