[pdal] Colorization filter slow?

[Howard Butler]

> On Oct 30, 2015, at 9:35 AM, Thomas Knudsen <knudsen.thomas at gmail.com> wrote:
> 
> Thanks Howard, for the quick diagnostic and workaround. We have
> checked it here and get similar results. Huge improvement! Looking
> forward to see what can be accomplished at the PDAL end of the
> pipeline.

Another GDAL sensitivity we're seeing here is GDAL's default cache settings are not very aggressive. Given the stripped TIFF file, setting the cache size to 500 allows the file to colorize nearly as fast as the tiled:

> [hobu at pyro (master)]$ export GDAL_CACHEMAX=500
> [hobu at pyro (master)]$ time ~/dev/git/pdal/bin/pdal pipeline striped.xml
> 
> real	0m19.034s
> user	0m15.557s
> sys	0m1.102s

I have updated the docs with information about this scenario http://www.pdal.io/stages/filters.colorization.html#considerations

There's maybe some more performance to get out of the colorization filter in how we are calling GDAL. I will investigate this a little bit more, but this setting should get you much closer to LAStools.

Howard