[OSGeo-Discuss] Open File Formats andProprietaryAlgorithms[SEC=UNCLASSIFIED]

Michael P. Gerlek mpg at lizardtech.com
Fri Aug 21 10:48:24 PDT 2009

> 10:1 compression rates without noticeable image quality reductions,

For some appropriate, workflow-specific definition of "noticeable".

Everything is a tradeoff.  I always tell people to run their own tests with their own datasets to determine what sort of quality they will achieve and what their users' workflows will require.


-----Original Message-----
From: discuss-bounces at lists.osgeo.org [mailto:discuss-bounces at lists.osgeo.org] On Behalf Of Paul Ramsey
Sent: Friday, August 21, 2009 11:36 AM
To: OSGeo Discussions
Subject: Re: [OSGeo-Discuss] Open File Formats andProprietaryAlgorithms[SEC=UNCLASSIFIED]

So hung up on wavelets, we are.

Internally tiled TIFF with JPEG compression and similarly formatted
internal overviews can achieve 10:1 compression rates without
noticeable image quality reductions, and as an added bonus can be
decompressed a heck of a lot faster than wavelet-based formats. The
wavelet stuff is k00l, in that there is no need for an overview
pyramid (it's implicit in the compression math) and much higher
compression rates can be achieved. But operationally, you can go a
long way with the more primitive (open image format + open compression
algorithm) approach.

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