[gdal-dev] Is there a way to create a spatial index in FGB if created without?

[Björn Harrtell]

So this (https://github.com/OSGeo/gdal/pull/6804) optimization by Even
might be helpful here.

In any case nice to see the limits of current FlatGeobuf impl. being put to
the test. 🙂

I suppose one could do an on disk sorting implementation but I'm not sure
it's worth the complexity of it and speed trade off.

If i can get to it would like to get some measurements done to properly
document the amount of RAM required as a function of number of features to
index.

Björn

Den tors 24 nov. 2022 19:38Even Rouault <even.rouault at spatialys.com> skrev:

>
> Le 24/11/2022 à 19:18, michael.smith.erdc at gmail.com a écrit :
> > I don’t believe these are huge features, its OSM building for the
> > world. Must be the memory constraint since it is a lot of features.
> > This doesn’t happen (i think, am retesting now) if created from the
> > osm pbf file directly but does from the fgb created from the pbf.
> Hum, it might be that the FGB reader is a bit gready in its memory usage
> then. Björn might be able to comment more
> >
> > Do either of the columnar formats (arrow, geoparquet) support spatial
> > access window selections yet (via ogr2ogr) or is that still forthcoming?
>
> There is no spatial index specification for those formats (yet ? it
> isn't obvious how to stick one into them, in a clean and backward
> compatible way, but I believe this is a subject of research). So for now
> spatial filtering involves scanning all features geometries (there are a
> few optimizations to make it as efficient as possible, but you
> definitely won't get a great performance if repeatedly selecting small
> amounts of features with different extents)
>
>
> --
> http://www.spatialys.com
> My software is free, but my time generally not.
>
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