Will Google help save the planet?

WE'RE not the first to discover this, but we'd like to confirm, from the crew of Apollo 17, that the world is round," said astronaut Eugene Cernan during the 1972 mission when the first clear image of the whole illuminated Earth was taken.

The picture, dubbed the "blue marble" by NASA astronauts, has likely "been seen by more human beings than any other image in the world", says Mike Gentry, a photo archivist at the NASA Johnson Space Center in Houston, Texas. "It was a symbol of hope for the future, unity and of a healthy planet."

Now geographers and environmentalists are hoping that a new set of images made freely available by the search engines Google and MSN Search will have a similar effect.

The release of Google Earth, a collection of bird's-eye photographs covering every inch of the planet, is likely to open up new advertising opportunities for the search engine and give it an edge over its rivals. But environmentalists say it may have another effect: revitalising the public's desire to preserve our beautiful but vulnerable planet.

"I think what Google has done could have the same kind of impact on people as the first images of Earth from the Apollo spacecraft," says Tim Haigh, a project manager at the European Environment Agency (EEA) in Copenhagen, Denmark.

The photos were taken by a variety of satellites and aircraft and have been stitched together and wrapped around a 3D virtual sphere that can be downloaded onto an ordinary PC from the internet (http://earth.google.com).

Google acquired the technology in October 2004 when it bought Keyhole, the company that owned it. The software was then made freely available at the end of June. A month later, rival search giant MSN released its own version, called MSN Virtual Earth, which is similar but does not yet cover the whole planet and is not as slick as Google Earth.

To run Google Earth you need a graphics-enabled PC equipped with a broadband internet connection. Once installed, it allows you to spin the Earth in three dimensions on the desktop and zip around the planet as if you were flying in a spaceship.

Some think that just looking at these images will be enough to inspire people to care for the planet. Others think it is the ability to zoom in on anything, from the Egyptian pyramids or the Grand Canyon to their own neighbourhood, that will highlight the Earth's small size and vulnerability.

Users can zoom in either by scrolling with the mouse or by typing a city name or zip code into the search line. The resolution ranges from covering 1 kilometre in many areas of the world to 15 centimetres per pixel in Cambridge, Massachusetts. Google says it is continuing to add new information to its database, and its goal is to refresh its images every 18 months.

"The ability to zoom from the whole planet down to the home and backyard will help people make the connection between themselves and their planet," says Allen Carroll, chief cartographer at the National Geographic Society in Washington DC. "Google Earth will no doubt raise awareness about how small and precious our Earth is."

But Pascal Gilles, who heads the European Space Agency's CryoSat mission to monitor precise changes in the thickness of the polar ice sheets and floating sea ice and is based in Rome, Italy, says it is not enough just to make images available. "If we want to make people aware of the limited resources of the planet, we have to embed the information in an image," he says.

The EEA is already working on a "neighbourhood" project that will embed environmental reports, land use and air emissions data inside free online geographical images of all the European countries, and is scheduled to go live by 2008. The National Geographic Society will also release a free, zoomable 3D image of the Earth later this year, similar to Google Earth, and has plans to embed environmental information within it.

But in theory environmentalists could simply create overlays or embedded links to environmental information that connect to Google Earth. The search giant has released tools on the Google Earth site that allow data to be overlaid on top of or embedded inside its satellite images.

So far this tool has not been used by environmental groups, but it has spawned hundreds of quirky creations and a website dedicated to them, which is called Google Earth Hacks (www.googleearthhacks.com).

One user has marked the Seven Wonders of the World onto Google Earth, and recorded them in a file as a tour on the Google Earth Community forum, which can be accessed via a link from the main site. Users downloading the tour are "flown" from the Hanging Gardens of Babylon right through to the pyramids, with links to information about each wonder.

But there could be a downside to putting these vast reservoirs of information at people's fingertips. If the resolution of the images is increased, people might object to a picture of their house being freely available.

Google and MSN's products might also make it easier to rehearse criminal attacks. There is a feeling that the ability to sail between the tall buildings of Manhattan, using Google's 3D "buildings" feature, would make a great training tool for terrorists. The Australian Nuclear Science and Technology Organisation has asked Google to consider censoring sensitive information.

Most experts dismiss these issues, however, and Google says: "The same information is available to anyone who flies by or drives over a piece of property."

Perhaps the most worrying issue raised by Google Earth and MSN Virtual Earth is that the public will assume their maps are always accurate. This was highlighted when the first users of MSN Virtual Earth quickly pointed out that the headquarters of rival company Apple were not at the appropriate location in the satellite pictures. MSN claims that this is because the satellite picture was out of date, but experts say the message is clear. "We are starting to rely on Google and Microsoft for our view of the world," says David Sonnen, a GIS consultant based in Bellingham, Washington. "I don't know what that means yet, but I do know that it's very important."

"Google Earth could have the same kind of impact as the first images of Earth from Apollo"