[GRASS-dev] Filter STDS by spatial index

[Veronica Andreo]

Hi Stefan

I'll test this weekend, would you mind providing us with a basic example to
test? Thanks a lot!!

Vero

El jue, 5 ene 2023 a las 11:01, Stefan Blumentrath (<
Stefan.Blumentrath at gmx.de>) escribió:

> Hi again,
>
> Please see:
> https://github.com/OSGeo/grass/pull/2725
>
> It uses east, west, north and south in the where statement to select only
> maps that overlap with a given spatial extent (e.g. the computatinal
> region).
> I would be happy to get a review of the PR, before proceding to eventual
> changes of module code...
>
>
> Cheers
> Stefan
>
>
>
>
> Gesendet: Montag, 26. Dezember 2022 um 17:31 Uhr
> Von: "Sören Gebbert" <soerengebbert at gmail.com>
> An: "Stefan Blumentrath" <Stefan.Blumentrath at gmx.de>
> Cc: grass-dev at lists.osgeo.org
> Betreff: Re: [GRASS-dev] Filter STDS by spatial index
>
> Hi,
> i am not sure if this helps: some t.rast.* commands should support a where
> statement. Maybe you can use east, west, north and south in the where
> statement to select only maps that are in a extent that is build in the
> where statement?
>
> Best regards
> Sören
>
> Am Mi., 14. Dez. 2022 um 15:24 Uhr schrieb Stefan Blumentrath <
> Stefan.Blumentrath at gmx.de[mailto:Stefan.Blumentrath at gmx.de]>:Hei,
>
> I do have a use case where I would like to filter maps in a STRDS by
> spatial extent before e.g. t.rast.univar processes all registered maps.
> In particular, I want to process only maps from a STRDS that intersect
> with the current computational region.
>
> The reason is that the maps registered in the STRDS are collections of
> single scenes of satellite images or collections of smaller mosaics that
> cover only parts of the total extent of the STRDS.
>
> Currently, that does not seem to be supported by TGIS, and I see two
> options to address that:
>     a) patch the scenes together with a given granularity (e.g. daily
> mosaics), leave GRASS GIS functions untouched and hope that there is some
> coverage for reasonable region settings. or:
>     b) add a spatial filter to the "get_registered_maps"[1] function
> in abstract_space_time_dataset.py, and then subsequently flags to relevant
> modules that make use modified function...
>
> For b) I would think that the most efficient way to handle it would be to
> add a where clause like it was done for the semantic labels? In that case,
> it may make sense to add an index for north, south, east, and west too, no?
> Maybe also top and bottom...
>
> My main question, however is if my case is just a corner case, or does
> some sort of spatial filteing possibility make sense in general / more
> broadly...
>
> Any feedback is much appreciated, esp. before I evtl. start working on b).
>
> Kind regards,
> Stefan
>
> 1)
> https://github.com/OSGeo/grass/blob/main/python/grass/temporal/abstract_space_time_dataset.py#L1604[https://github.com/OSGeo/grass/blob/main/python/grass/temporal/abstract_space_time_dataset.py#L1604]
>
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