04:07 PM CDT on Wednesday, June 14, 2006

By WALT ZWIRKO / WFAA-TV

Google

Google Earth's tantalizing view of Cabo San Lucas, Mexico.

The word "impressive" seems insufficient to describe the latest version of what has to be one of the biggest software bargains of the 21st century: Google Earth .

Google Earth takes a traditional atlas and makes it come alive on your computer screen.

Type in a place name (or just point to a spot on the globe) and it takes you there, in three-dimensional glory.

Not only can you get the traditional "look straight down" perspective on the landscape—which is generated by a mix of satellite imagery and aerial photography—but the software can generate angles, so you can "fly" over terrain like a helicopter.

You've probably seen major TV networks use Google Earth to help viewers understand the spatial relationships between places on the map.

In 39 U-S cities (including Dallas) you can choose to represent buildings as polygons (although someone apparently forgot to tell the programmers about the ball on top of Reunion Tower, which is represented as a tall column).

While Google Earth was first introduced last year, this new version has improved navigational features, better resolution, and it easily implements clever add-in features.

For instance, clicking on a "placemark" (a bookmark that contains positioning information) lets you overlay the maps with real-time flight information, tracing the route of each aircraft with a magenta-color line.

Because the software lets you view the scene at an angle, you can actually gauge the altitude of the planes in relation to an airport—not unlike having a seat in the control tower.

Another placemark lets you compare today's view of San Francisco with views from previous years by superimposing historic aerial photography on the most current data.

I found a placemark with the routes of London's Underground rail system.

And someone even posted a placemark that plots the path of Tropical Storm Alberto on Google Earth.

All users benefit from the community nature of this product, with individuals around the world adding key details that traditional cartographers might never consider.

The software is especially impressive considering the fact that I was using an older home computer with a poky 1 gigahertz processor to generate the images.

However you view it—from the volcanic peak of Mount Saint Helens to the majesty of the Grand Canyon—Google Earth is an incredible achievement, suitable for simple desktop world exploration or serious geographic study.

And if the free, basic version doesn't meet your needs, Google Earth sells several versions targeted at researchers and businesses.

Let's put it this way: If you only download one free software product this year, make it Google Earth.

Watch Computer Corner every Wednesday on News 8 Midday at noon, or online any time.

E-mail askwalt@wfaa.com