[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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