Better TIF image rendering?

[Frank Warmerdam]

On 1/31/06, Luca Manganelli <luca76 at gmail.com> wrote:
> Hi, I wonder if there is the possibility to have a better TIF rendering.
> We have ECW ortophotos, converted in TIF for more speed.
> But if we see entire map in ECW, the quality is far better than TIF.
> I think that the ECW module applies an antialiasing system, while TIF
> doesn't.
> Is there a way to improve rendering quality for TIFs?

Luca,

I would suggest pre-building overviews for the TIFF, and using
the averaging option as opposed to the default which is just
decimation.   You would use a command like the following to
build overviews with averaging.

  gdaladdo -r average abc.tif 2 4 8 16 32 64

Generally speaking averaging will give "smoother" results at
overview levels than the default decimation technique for building
overviews.  If you have no overviews, implicit decimation is done.

Best regards,
--
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent