[QGIS-Developer] Processing: questions on temporary files

[Nyall Dawson]

On Thu, 5 Dec 2019 at 17:35, Alexander Bruy <alexander.bruy at gmail.com> wrote:
>
> There is a FlatGeoBuf [0], probably we can use it or at least get some ideas.
>
> [0] https://github.com/bjornharrtell/flatgeobuf

FlatGeoBuf indeed looks very exciting!

But to be honest, I think an easier path would be just to directly
serialize the qgis features to disk -- we already have
QgsFeature::operator<< and >> to read and write features to data
streams (without loss of any information), so we could utilise those
during the disk read/write.

Nyall


>
> чт, 5 груд. 2019 о 09:18 Richard Duivenvoorde <rdmailings at duif.net> пише:
> >
> > On 05/12/2019 01.01, Nyall Dawson wrote:
> > > What's needed/missing is a method for the memory data provider to
> > > detect when a layer is growing too large, and start writing this out
> > > to disk. (Important note: we CAN'T use any of the standard spatial
> > > formats for this (as they are lossy when compared to the memory
> > > provider support), so we'd need to directly serialize the memory layer
> > > features to a custom binary format, with indexing support for rapid
> > > retrieval of features.
> >
> > If I understand correct, FME is also working with (indexed) temp files?
> > I'm not an FME user, so I can bu wrong, but I always wondered what kind
> > of format that is...
> >
> > IF we (as FOSS community) could come up with some (new?) indexed file
> > format, it (besides being a in-between product for transformations) also
> > a potential data exchange format (maybe some zipped version of file+index?)?
> >
> > Anybody into this?
> >
> > Regards,
> >
> > Richard Duivenvoorde
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>
>
> --
> Alexander Bruy