On Fri, 27 Nov 2020 at 01:52, Andreas Neumann <[email protected]> wrote:
>
> Hi all,
>
> Thanks for your replies/opinions.
>
> @Richard: this message also comes up for intermediate memory layers, not only 
> for Geopackage layers.
>
> @Luigi: if I manually add "create spatial index" often, this very much 
> "pollutes" the model.
>
> I agree with Ujaval, that it would be a better user experience if QGIS would 
> do the indexing automatically (on intermediate layers) for operations where 
> the input doesn't have an index and the algorithm would potentially benefit 
> from an index.

This is a fair enough request -- we could keep the index generation as
a "lazy" thing which is only done when a step in the model indicates
that it's about to benefit from it. I can't see any technical
blockers/disadvantages to this.

>
> Next to automatic indexing I would think that "auto-repairs" for errors that 
> processing algorithms introduce would be good to have, e.g. remove double 
> vertices, remove empty geometries, empty holes/rings, self-intersections. 
> etc.. If this is potentially dangerous, we can do opt-in with central 
> threshold values, and only if the analysis is 2d only. I understand that for 
> 3D analysis automatic cleaning is not always possible.

There's some discussion on this here:
https://github.com/qgis/QGIS/pull/39891#issuecomment-734676128

Nyall

>
> Or maybe a switch to GEOS 3.9 with the "fixed precision model" enabled would 
> remove all these errors previously introduced by processing?
>
> Greetings,
>
> Andreas
>
> On 2020-11-26 16:24, Ujaval Gandhi wrote:
>
> +1 to have an option to generate spatial index automatically for intermediate 
> layers. As I understand, creating index for database layers automatically may 
> not be preferable, but it's reasonable to want this for intermediate memory 
> layers. Since processing can already identify which operations might benefit 
> from the index, it would be much better user experience to take care of it 
> internally.
>
> Ujaval Gandhi
> Spatial Thoughts
> mobile: +91-8095684687
> email: [email protected]
>
>
>
> On Thu, Nov 26, 2020 at 8:26 PM Luigi Pirelli <[email protected]> wrote:
>
> I've this message constantly... but usually when an intermediate layer is 
> used in some geoprocess. So, you can just add a "create spatial index" step 
> before the next geoprocess. Doing it automatically can be time spending. Do 
> you really need it everytime?
>
> Luigi Pirelli
>
> **************************************************************************************************
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> **************************************************************************************************
>
> On Mon, 23 Nov 2020 at 15:23, Andreas Neumann <[email protected]> wrote:
>
> Hi,
>
> When running QGIS processing models, I frequently get the red warning 
> messages:
>
>
> No spatial index exists for input layer, performance will be severely degraded
>
>
>
> These are temporary (intermediate) geopackage files that QGIS generates 
> during the running of the model. Is there an option that QGIS could 
> automatically generate these spatial indexes for intermediate files?
>
>
>
> Thanks,
>
> Andreas
>
>
> --
> Andreas Neumann
> QGIS.ORG board member (treasurer)
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