[gdal-dev] Shapefile index .qix vs. sbn/sbx

[Even Rouault]

Hi Jukka,

>
> If both both .qix and sbn/sbx spatial indexes are present, which one GDAL is
> picking?

I've just checked. .qix is picked up in priority. But it might be difficult to
get into that situation, since the OGR shapefile driver should delete any
existing .qix or .sbn before building a new .qix.

> Is the feeling still the same as in
> http://erouault.blogspot.fi/2012/06/gdalogr-using-shapefile-native-sbn.html
> that sbn/sbx is faster with big shapefiles?

I haven't had any third-party confirmation of this, but this probably doesn't
make a huge difference ultimately. .sbn might be a little less CPU intensive
than .qix, but this might only show in artificial situations where data is
already cached by the operating system (accessing to the shapes is what take the
most time), and when you exercice a lot the spatial index. When just scrolling
in QGIS, I bet nobody can tell the difference.

Even