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.'"

okay..

[derxob]

I better cover up my illegal plants..

Is this nitpicking?

[Vila, Bob]

The estimate is that up to 20 terabytes of imagery will be needed to mosaic together the final worldwide GLOBCOVER map - an amount of data equivalent to the contents of 20 million books.

Why do writers insist on making these kind of useless comparisons? Is there any research that indicates the average book contains the equivalent of one megabyte of data? Especially one megabyte of imagery? Will this really help a layperson quantify a terabyte?

This just in: The human brain is capable of storing an amount of data equivalent to 68 quintillion index cards.

Re:'hello mum'

[zeromemory]

Unless you have a roof the size of large chemical processing plant, your house won't appear to be more than a speck of dust.

The satellite imagery for this is being recorded at a resolution of 300 m. For comparison, the most zoomed in you can get on GoogleMaps is 2 m per a pixel.

240 bits per pixel = lots'o'data

[G4from128k]

MERIS grabs data in up to 15 spectral bands with 16 bits per band per pixel. Its only has a 1/2 megapixel imager (842 x 691), but the RAW images are 17.5 MB.

Multispectral data is great for identifying ground cover (e.g, classifying the types of plants, health of plants, minerals, etc. on the ground). Sometimes, it's more valuable to know the materials on the ground than to see the geometric detail.

publicy available?

[Anonymous Coward]

It'd be great if I could download freely the maps. I know, it's a huge effort, but so are my efforts when I work and pay my taxes.....

Re:vegetation

[TripMaster Monkey]

The fact is, there is more vegetation on the planet now than there was 100 years ago

I call bullshit.

State your references or admit you're pulling 'facts' out of your ass.

Google maps fanboys, have no fear...

[jeffmeden]

There is a huge difference between the 'google maps' visual coverage, and this, which is a 'earth surface condition map'. For one, the resolution here is pathetic compared to that of the 'google maps', but it has a completely different goal. It is intended to show details about land, instead of whether or not someone mowed a 'hi mom' message into their lawn. Move along, you won't be seeing that any time soon.

Re:Google it up!

[kebes]

For those who don't know: the images that google makes available at maps.google.com are not the best they have access to. Google bought Keyhole [keyhole.com] and shortly thereafter launched google maps. However, anyone who did a keyhole free trial knows that the keyhole database had very high resolution images of the whole planet. What you see in google maps is about half the resolution that keyhole has. Not only that, but keyhole had imagery for the whole planet.

My point is that google is not limited in what it has available. Obviously they are releasing lower rez images for google maps (and charging for the keyhole service for professionals that need the higher rez), and it's also taking them some time to get google maps working for other parts of the world. But they already have access to a very extensive database (although possibly there are some licensing issues?).

Re:vegetation

[TripMaster Monkey]

US forestlands covered 732 million acres in 1920; today they cover 747 million acres.

A gain of 15 million acres over 85 years.

Roughly 176,471 acres gained a year.

Meanwhile, worldwide, we are losing rainforests to the tune of 1.5 acres per second [rain-tree.com].

That works out to 47,336,400 acres lost a year...more than 268 times the rate forestlands are growing in the U.S.

Re:'hello mum'

[d-Orb]

The difference between stuff like google maps, and that sort of data (from the Quickbird or Ikonos satellites, with resolutions better than a meter) and MERIS (the instrument used for GLOBCOVER) or MODIS (the NASA equivalent. There before MODIS, slightly lower resolution, but you can get the data for the FTP site without the hassles you have to go through to get MERIS data. But I rant...) have poorer spatial resolution (MERIS full resolution is 300m, and MODIS is 500m), but better spectral and temporal sampling.

In other words, the stuff often available from the very high resolution sensors is mostly equivalent to aerial photography (albeit from a bit higher up than your normal plane): RGB and a panchromatic image. In the case of MERIS and MODIS (and NOAA's AVHRR, Landsat, etc) you do get the extra spectral information which helps to improve classifications and do all sorts of funky other things. GLOBCOVER thus needs to be compared with stuff like this [umd.edu] rather than with photogrammetric maps.

I believe that, politically, GLOBCOVER is just an ESA posterboy to show MERIS off. While MERIS is a nice instrument (very nice indeed), it's just an improved MODIS, and ESA seems worried that few people are making operational use of MERIS. This has a number of reasons. In many cases, environmental monitoring and modelling communities are encumbered by the lack of high level products (they are given a set of images and told: try your best to estimate the fraction of photosynthetically absorbed radiation). MODIS solves this by actually making these interesting measurement available.

That was a bit of a rant, wasn't it?

Re:vegetation

[starman97]

That number does not make a distinction between old-growth forest which is bio-diverse and mono-culture treefarms which have very limited habitat for anything but genetically-engineered fast growth pine trees.

Re:Why is this news now?

[greppy]

Note there are no direct links to Rolands site in the article. Unless it's been edited between your viewing and mine. A gesture to temper the baying mob?

Re:I want my planet!

[birge]

European governments keep themselves busy by making everything as difficult as humanly possible. It's either that, or cause a world war every few years. I applaud this decision.