[Qgis-user] Historical data in QGIS-PostGIS

[chris hermansen]

Brent, Vanildo, list;

On Fri, Nov 13, 2020 at 5:23 PM Brent Wood <Brent.Wood at niwa.co.nz> wrote:

> I think this is straightforward, if I understand you correctly...
>
> Assuming each year comprises a separate version of the data, have the year
> as a column in the table, which allows you to select by year, group by year
> in the database, on an indexed integer value, which is very fast.
>

This is true if all the spatial elements are discrete and newer versions
fully replace older versions.  However if they group and ungroup I'm not
sure how that would be maintained in your scenario.  Having said that, I'm
not sure if SPI will support that either.

On page 272 of Obe and Hsu PostGIS in Action the authors talk about time
travel and the KNN operator; they say "Backwards time travel is something
PostGIS does not yet support!".

So it may also be worthwhile to pursue this KNN operator business.


-- 
Chris Hermansen · clhermansen "at" gmail "dot" com

C'est ma façon de parler.
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