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85. Exploring Earth and Sky

By Andrew D. Wright

The urge to explore has driven humanity since the dawn of time. The lure of what is beyond the next rise captivates us today just as it captivated our ancestors.

There are free software packages that allow you to explore in ways you've probably never imagined.

Google Earth is one such program. Free to download and use, it's available for Windows 2000/XP and Macintosh OS X 10.3.9 or newer.

You start with a detailed view of a cloudless Earth. With the scroll wheel of the mouse you can zoom in and out. As you move in closer to the land, sharper satellite photos are downloaded. Most places will allow a sharp enough view to identify house rooftops and individual cars on the road at the best resolution. Navigation is intuitive; you click and drag to move the landscape beneath your cursor.

You can also tilt the view and fly across a three dimensionally rendered landscape. Google Earth downloads topographical information as well as satellite images so hills stand up and valleys form hollows. Moving across a mountain range looks incredible. The 3D effect can be exaggerated to emphasize landmark features. The better quality your video card, the better the 3D rendering looks.

Major urban centers such as New York even have the buildings rendered so you can fly over the city and see the mass of skyscrapers and forests of smaller buildings standing up from the ground. There are more features than space to list them here.

For the more advanced explorer, American space agency NASA has a program called World Wind. Offering the same kind of 3D landscape rendering and zoom features as Google Earth, World Wind offers a choice of satellite views and many add-ons for extra views and features.

World Wind is a free download and requires Windows 2000/XP with Microsoft's .NET runtime environment installed.

In addition to multiple views of Earth, World Wind includes high resolution views of the Moon, Mars, Venus and Jupiter. You can fly over the top of Mons Olympus on Mars like you were really there, and spin the King of the Planets like a child's toy. Additional plugins can be downloaded which let you fly through the accurately rendered rings of Saturn or view the damage to New Orleans from Hurricane Katrina.

One of the more addictive of the World Wind plugins is a detailed sky survey called SDSS. As you zoom in, the nearer stars move past you and sharper sky images are downloaded showing more detail. You zoom in further and more details emerge. Your virtual view moves out dozens of light years, then hundreds and the detail keeps getting finer and finer, as it would in real life if you could explore the other side of the sky.

Having a large hard drive to store all the picture files and a fast Internet connection to download them are pluses. Home-based explorers will find lots to keep their interest.


Google Earth (free):

NASA World Wind (free):

World Wind add-ons (free):

The Mousepad runs every two weeks. It's a service of Chebucto Community Net, a community-owned Internet provider. If you have a question about computing, email If we use your question in a column, we'll send you a free mousepad.


The Mousepad Index


Originally published 4 June 2006


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