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-boun...@lists.osgeo.org [mailto:discuss-boun...@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 <lbl...@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 Warning: Information provided via electronic media is not guaranteed against defects including translation and transmission errors. If the reader is not the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this information in error, please notify the sender immediately. _______________________________________________ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
_______________________________________________ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss