[OSGeo-Discuss] Open File Formats and Proprietary Algorithms

Eric Wolf ebwolf at gmail.com
Thu Aug 20 13:53:11 PDT 2009


Interesting... I can understand why NAIP was in MRSID. It's a pretty large
dataset - and I think .SID was more widely supported than JP2 until
recently. The USDA site does provide links to PCI Geomatics FreeView, which
can read .SID format but not save it. IrfanView, with a plugin, can read SID
format and convert. So it's not a dead-end format. And it sure beats SDTS!
I think data interchange and real interoperability has only recently been
possible for large raster datasets. It's still a chore if you have to
re-project large raster datasets. This may add some content to a research
paper I'm working on.

-Eric


-=--=---=----=----=---=--=-=--=---=----=---=--=-=-
Eric B. Wolf                    New! 720-334-7734
USGS Geographer
Center of Excellence in GIScience
PhD Student
CU-Boulder - Geography



On Thu, Aug 20, 2009 at 2:22 PM, Landon Blake <lblake at ksninc.com> wrote:

>  Eric,
>
>
>
> The imagery I am talking about is from the USDA APFO:
>
>
>
>
>
> This FAQ contains a snippet about the format:
>
> http://www.fsa.usda.gov/FSA/apfoapp?area=home&subject=prog&topic=nai
>
>
>
> In an interesting turn of events I note that as of 2008, the USDA is
> releasing the county mosaics in JP2 format, not in MRSID. I am not sure what
> brought about this change, and I wasn’t aware that it had been made. The
> same web page indicates that there is a shapefile index for the individual
> image tiles.
>
>
>
> It appears that you can also download the county mosaics online.
>
>
>
> A lot of this has changed (improved) in the last couple of years. I’m glad
> I checked again. That being said, the principles from our discussion still
> apply. :]
>
>
>
> *Landon*
>
> Office Phone Number: (209) 946-0268
>
> Cell Phone Number: (209) 992-0658
>
>
>
>
>   ------------------------------
>
> *From:* discuss-bounces at lists.osgeo.org [mailto:
> discuss-bounces at lists.osgeo.org] *On Behalf Of *Eric Wolf
> *Sent:* Thursday, August 20, 2009 1:15 PM
> *To:* OSGeo Discussions
> *Subject:* Re: [OSGeo-Discuss] Open File Formats and Proprietary
> Algorithms
>
>
>
> The MRSID format is a very special case - and perhaps an opportunity for a
> new FOSS file format. MRSID is a lossless, fractal-based, multi-scale raster
> compression format. LizardTech has the algorithms to encode and decode MRSID
> locked up in copyrights, and I believe, patents. Even companies like ESRI
> shell out big bucks to LizardTech to be able to read and write the MRSID
> format.
>
>
>
> I guess I missed the context of the discussion. Is the government releasing
> certain data exclusively in this format? If so, I think the argument can be
> made against this practice. The different in compression between MRSID and
> gziped TIFFs isn't really that great in this day of cheap disks and fat
> pipes.
>
>
>
> -Eric
>
>
> -=--=---=----=----=---=--=-=--=---=----=---=--=-=-
> Eric B. Wolf                    New! 720-334-7734
> USGS Geographer
> Center of Excellence in GIScience
> PhD Student
> CU-Boulder - Geography
>
>
>  On Thu, Aug 20, 2009 at 12:27 PM, Landon Blake <lblake at ksninc.com> wrote:
>
> I realized that publishing a spec for a file format like MRSID isn’t as
> clear cut as I had at first thought. If the MRSID software uses a fancy
> top-secret compression/decompression algorithm to move data to and from the
> file format knowing only the structure of the format would do no good. You’d
> have to release the details of the algorithm as well.
>
>
>
> I still don’t think proprietary file formats are a good idea for government
> data released to the public, but I admit that having a company like
> LizardTech publish a spec for something like MRSID is not necessarily a
> simple task. No doubt a lot of time and money goes into developing those
> algorithms.
>
>
>
> This makes me wonder about algorithms used to purposefully encrypt binary
> file formats. That is another can of worms. It looks like the easiest thing
> to do is to start with a file format that was designed to be open from the
> very beginning.
>
>
>
> Landon
>
>
>
>
>
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