[gdal-dev] .ovr files and Lanczos

[Robb Wright]

I'm working with indexed color types of raster data (charts).  The data 
is in RGB geotiffs and I'm using gdaladdo to create pyramid layers for 
them.  Unfortunately, the best method for this raster type available 
using gdaladdo is still pretty bad - much of the linework becomes 
garbled when viewing the pyramids.  The best-looking method that I've 
been able to come up with is:
gdaladdo.exe --config COMPRESS_OVERVIEW DEFLATE -r average

The Lanczos algorithm method works beautifully when used with other 
programs - but I need to create .ovr files.  gdal_retile.py output looks 
great - but I can't figure out how to create .ovr files from that output.

Does anybody know of the availability of the Lanczos resampling method 
for gdaladdo - or of another way to create .ovr files with Lanczos?

Robb