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The Sharpest Ever Global Earth Map
Roland Piquepaille writes "The GLOBCOVER project, started by the European Space Agency (ESA), has a very simple goal. It will create the most detailed portrait of the Earth's land surface with a resolution three times sharper than any previous satellite map. The image acquisition will be done throughout 2005 and use the Medium Resolution Imaging Spectrometer (MERIS) instrument of the Envisat environmental satellite. To create this sharp map, the GLOBCOVER project will analyze about 20 terabytes of data gathered by the European satellite. When it's completed, the map will have numerous uses, 'including plotting worldwide land use trends, studying natural and managed ecosystems and modelling climate change extent and impacts.'"
(BTW, I *highly* recommend checking out World Wind if you haven't seen it. It is one of the most awesome programs ever to exist, bar none.)
main(c,r){for(r=32;r;) printf(++c>31?c=!r--,"\n":c<r?" ":~c&r?" `":" #");}
Well but isn't this data for which I've paid with my tax euros already? Why does the public who financed it not get free access to that data?
While we're at it, can other Slashdotters perhaps point to links of freely available satellite imagery? Is there any kind of systematic coverage of the planet we live on which is freely available to everyone who does happen to live here?
You could download Nasa Worldwind software for free.
There are some issues with Landsat7 data, but hopefully they will get fixed soon.
Its awsome piece of software! offers 7m resolution globally and offers 1m resolution for USA.
On the other hand, ESA has always been stingy in giving access to data. It took them a while to release Titan images; as opposed to Nasa who makes them available almost instanteneously.
I guess thats the difference between the cultures!
- Sh!t
You are missing something.
The resolution of this bird is 300 meters, in many more wavelengths than just visible - multiple longband IR, optical, synthetic apeture millimeter radar.
It's like the difference between a 1920x1080 one bit per pixel image and a 640x480 Truecolor image.
www.eFax.com are spammers
Reading the article, it really is 300m/pixel. This is 400x lower resolution than the 15m Landsat data that is available as a basemap in Keyhole, Google Maps, and other providers.
The reason this data is interesting is its 15-band nature and the amount of analysis and extraction that can be done from it.
For pretty pictures, there are plenty of better sources.
Current multispectral stuff is more than 300m? Interesting, it would miss entire steams, even rivers and stuff.
Good point and that seems plausible, but is not entirely true. With a good pixel-mixing analysis you can resolve stuff inside the pixel. The key is having a clean spectral model for the terrain versus water and being able to say that a given pixel looks like its 90% trees and 10% fresh water. "Unmix" enough pixels and you can string them together to find streams smaller than 300 m wide that cross an expanse of forest or grass-land. A string of 10% water pixels in a 300 m resolution image is probably a 30 meter-wide stream. Moreover, the plants around water often different substantially from the plants in the drier surrounding areas -- making it even easily to infer the existence of creeks that are far smaller than the resolution limit.
Two wrongs don't make a right, but three lefts do.
Holly Crap People RTFA, and if you don't understand TFA then STFU!
/.ers that compare everything to google, but for real scientists. K, I'm done venting now.
This is not imagary for you to be able to spot yourself fingering,mooning or otherwise exposing yourself to the sattelite. It is a Land Cover map, meaning it will be used for classifications . . ie, Forest, urban, Prairie, Water etc. The reason such a teribly poor, crappy, worse than google maps resolution is used, is becuase if you havew a very fine resolution, classification becomes difficult. In a city, for instance, every tree would become forest, even if right next to a house. Some degree of homogeneity is needed in the image to make classification meaningful. It will be a useful project, maybe not for stupid
You got your calculation wrong because you don't get the operating principle of the MERIS instrument. It is not a half megapixel ordinary camera that with some magic collects 15*16 bit per pixel (e.g. by taking 15 images in close succession with a changing filter wheel).
As the page on MERIS says, it is a 'pushbroom imaging spectrometer'. 'Pushbroom' means that instead of a rectangular field of view like a normal camera, it has a line-shaped field of view. An image is formed by continuously observing the single line and wait for the the satellite to 'sweep' the whole planet. 'Imaging spectrograph' means that the previously mentioned line is spectrally separated (with a prism or a grating) perpendicular to the line. You then get an image on your CCD where one direction corresponds to the distance along the line and the other is formed by the different colors.
The optics details of the system are here, an description of the CCD is here. If I understand it correctly, one line is 740 pixels wide and the colors are 'binned' in 15 different spectral bands. That gives you 740*15*2=22200 bytes per line. How much that would be per picture depends on the height of the image, which depends on how long you collect data. In principle you could have it sweep the whole planet non-stop.
karma police: arrest this man, he talks in maths; he buzzes like a fridge, he's like a detuned radio. [radiohead]