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Massive Mosaic of Canada
rvr writes "Thanks to compression technology that has reduced the file to 3.3 gigabytes and a collaboration between the Canadian Forest Service and the Canadian Space Agency called the 'Earth Observation for Sustainable Development of Forests', this gigantic image -- the highest-resolution image of Canada freely available -- can now be downloaded to your computer."
Except that you can't:
To learn how you can obtain a copy of the Canada Mosaic, contact Jeff Dechka, Remote Sensing Data and Product Coordinator at the Canadian Forest Service's Pacific Forestry Centre in Victoria at jdechka@pfc.cfs.nrcan.gc.ca
Oh well.
Having worked on GIS imagery before (from the Australian government), I'm assuming it's in MrSid format. The 100:1 kind of compression ratios are completely legit, it's really incredible. I believe it uses fractal compression of some sort. It's produced by LizardTech.
JPEG and JPEG2000 are great for compressing images where you care more about how it looks than preserving the actual data since they use psychovisual enhancements. MrSid does a much better job at preserving the integrity of the data at much much higher compression rates.
I have found MrSID compression to be extremely lossy beyond about 20:1. (That's still alot!) I agree - jpegs suck for mapping. My 0.02.
"If you think you have things under control, you're not going fast enough." --Mario Andretti
I'm not sure if this is high-res enough for you, but you might want to try Terra Server.
It seems to work fairly well for US locations, and not work well for other (Canadian) searches.
Are high resolution satellite/aerial images available for other locations?
Yes. Do a google for your state/province and "GIS data". Most US states have some sort of FTP setup with elevation maps, aerial images, and topographic maps to download.
No, I don't expect to be able to buy hi-res images of Area 51, but was looking for my neighborhood.
Actually, I used to work for Space Imaging, and their conference demo was a 3D flyover of Area51 that had elevation and 1-meter resolution color imagery. To get a quickie on your neighborhood, check out Terraserver.
Also, are there ways of getting really nice poster prints of high resolution images?
www.mytopo.com
USGS extension office
Space Imaging has some famous stuff for sale as posters (pyramids, WTC site, etc.)
"If you think you have things under control, you're not going fast enough." --Mario Andretti
LizardTech make some other awesome products such as Genuine Fractals for Photoshop. Incidentally this is also used by DSLR photography enthusiasts to sharpen their images better than most traditional techniques are able to achieve.
MrSid is kinda a proprietary format though, which is unfortunate. When I needed to extract a MrSid file under Linux to a JPG format, I had to run the free (beer) DOS binary version of the MrSid converter that they provide, inside of Wine.
I seem to recall them offering some sort of binary-only Linux version, that didn't work or something. I know I couldn't get a JPG of the whole image out of it.
I've had enough abrasive sigs. Kittens are cute and fuzzy.