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

Landon Blake lblake at ksninc.com
Fri Aug 21 11:57:35 PDT 2009


Ivan,

Ignoring the danger that this thread will devolve into a discussion about different raster formats, I will ask you for some specifics.

What are the limitations of Geotiff/JPEG compared with the proprietary alternatives?

Maybe we need to cook up a "Guide To Raster Data File Formats for Storage and Distribution of Public Data". :]

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 Lucena, Ivan
Sent: Friday, August 21, 2009 11:54 AM
To: Bob Basques; OSGeo Discussions
Subject: RE: [OSGeo-Discuss] Open File FormatsandProprietaryAlgorithms[SEC=UNCLASSIFIED]

Bob,

Sorry to mess with discussion but if someone is suggesting the use of Geotiff with JPEG compressed as a "Open File Format" (copied and pasted from the thread title) I would like to remember myself and the audience obout the data type limitations. 

There's more in raster data than meet the eye, and that usually doesn't come in unsigned integer 8  bits. :)

Regards,

Ivan

>  -------Original Message-------
>  From: Bob Basques <Bob.Basques at ci.stpaul.mn.us>
>  Subject: RE: [OSGeo-Discuss] Open	File	FormatsandProprietaryAlgorithms[SEC=UNCLASSIFIED]
>  Sent: Aug 21 '09 13:27
>  
>  All,
>  
>  
>  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.
>  
>  
>  bobb
>  
>  
>  >>> "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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