[gdal-dev] .ovr files and Lanczos

[Chaitanya kumar CH]

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 <robbkwright at 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 <robbkwright at 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 at 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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