[OSGeo-Discuss] Open File FormatsandProprietaryAlgorithms[SEC=UNCLASSIFIED]

Bob Basques Bob.Basques at ci.stpaul.mn.us
Fri Aug 21 11:27:42 PDT 2009


Can someone remind me again, are we talking about saving space, or making it easier to implement something . . .  :c) 

I personally prefer nice simple internal pyramided tiles with indexing, about 10% extra space, and very good performance. 

Someone earlier in this thread spoke about some of these technologies being somewhat obsolete what with the new network and bandwidth speeds available for publishing. 


>>> "Lucena, Ivan" <ivan.lucena at pmldnet.com> wrote:

But you can't compress data types other than byte in JPG. Can you do that in JP2K?

>  -------Original Message-------
>  From: Landon Blake <lblake at ksninc.com>
>  Subject: RE: [OSGeo-Discuss] Open FileFormatsandProprietaryAlgorithms[SEC=UNCLASSIFIED]
>  Sent: Aug 21 '09 12:42
>  Paul,
>  I was wondering the same thing.
>  It seems a little like choosing to drive a Honda Accord, or a Ferrari.
>  The Ferrari is a lot faster and comes with a better looking trophy wife
>  (or husband), but the Honda is a lot easier to fix. (Try finding an
>  affordable Ferrari mechanic in Stockton, California.)
>  To tie this back into our original discussion, it seems like the
>  government should be choosing to drive a Honda Accord when it can,
>  instead of the Ferrari.
>  I guess you'd really have to crunch the numbers and see if the savings
>  in bandwidth/disk space costs were really worth the compression savings
>  that result from a proprietary compression scheme ("wavelet black
>  magic").
>  The problem with this is a lot of the benefits that come from the Honda
>  Accord (open image format + open compression algorithm) aren't easily
>  calculated in dollars and cents.
>  Still, this speaks to an important truth I have discovered in open
>  source development: Simple is better, even when it isn't necessarily
>  faster and smaller.
>  I'd rather have code that I can understand, or a file format that a
>  programmer in 20 years will understand, than a Ferrari you can't drive
>  unless you have a PHD and did a thesis on wavelet compression. :]
>  Landon
>  Office Phone Number: (209) 946-0268
>  Cell Phone Number: (209) 992-0658
>  -----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 10:36 AM
>  To: OSGeo Discussions
>  Subject: Re: [OSGeo-Discuss] Open File
>  FormatsandProprietaryAlgorithms[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.
>  P.
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