Robb, Note that the quality is effected by the levels you choose. Can you provide a small part of the image where the overview is garbled the most.
On Tue, Nov 29, 2011 at 12:00 PM, Robb Wright <robbkwri...@gmail.com> wrote: > Thanks Chaitanya. Unfortunately gdaladdo doesn't support the Lanczos > resampling type. Lanczos creates - by far - the best looking downsampled > images for my type of rasters. What I'm looking for is a way to create > pyramid layers/.ovr files using the Lanczos resampling method. > > Robb > > > On 11/29/2011 12:58 AM, Chaitanya kumar CH wrote: > > Robb, > > If you are using gdal version 1.6 or later, you can use the -ro option[1]. > It opens the tiff file in read-only mode and creates external overview. > > [1]: http://www.gdal.org/gdaladdo.html > > On Mon, Nov 28, 2011 at 11:53 PM, Robb Wright <robbkwri...@gmail.com>wrote: > >> >> 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 >> _______________________________________________ >> gdal-dev mailing list >> gdal-dev@lists.osgeo.org >> http://lists.osgeo.org/mailman/listinfo/gdal-dev >> > > > > -- > Best regards, > Chaitanya kumar CH. > > +91-9494447584 > 17.2416N 80.1426E > > > -- Best regards, Chaitanya kumar CH. +91-9494447584 17.2416N 80.1426E
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