Issue: Volume: 23 Issue: 10 (October 2000)

All-Terrain Visualization

Tracking the Tour de France on the Internet

By Karen Moltenbrey

You don't have to be a cycling enthusiast to realize just how grueling the 23-day, 2276-mile Tour de France is. The intensity of the world's premier bicycle race was apparent to all who witnessed the pained looks on the racers' faces last summer as cameras captured their expressions during the various ascents up France's steep mountain passes. But those who wanted a more intense feel for the route's terrain could log on to the Web for a 3D interactive flythrough of the course.

"Our coverage of the 2000 race focused on the difficult-terrain stages, where our 3D technology could show the Internet audience just how difficult this race really was," says Arik Katz, vice president of engineering at Skyline Software Systems, the Waltham, Massachusetts, company that created the unique 3D views from satellite and aerial imaging data with its proprietary technology.

For the second year, Skyline has provided a 3D view of the race to visitors of the Tour de France Web site ( 2000/us). During the race and for an undetermined period following its completion on July 23, users can view six out of the 21 stages of the race as static 3D images using Skyline's TerraPhoto3D technology. For this PC- or Mac-based application, which doesn't require any downloads, the Internet user requests a 3D version of an image from the Web site, which Skyline renders before sending it to the user.

For a higher level flythrough view of the course, where users can interactively view and navigate the photorealistic environment, they must first download Skyline's TerraExplorer viewer, which is free and available only for the PC, through a link from the Tour de France Web site. Rendering is then performed on the user's machine.
Skyline Software Systems used its Terra product line to provide Internet users with a 3D view of the Tour de France bicycle race. Users could view a static 3D image of the course or navigate an interactive flythrough model.

During the race, the site also provided a real-time view of the cyclists' progress, using a Global Positioning System (GPS) unit mounted on a motor cycle traveling with the riders. "With this, we could show the actual location of the race leaders in real time," says Katz. (The units were too heavy to be placed on the bikes.)

The Skyline team then superimposed the information as a 2D moving icon onto the static 3D terrain model of the course. The tracking data can be updated approximately once a second, to show continuous movement of the riders, Katz adds. Using this application, fans could check the location of the riders before going to meet them as they rode through their towns, without having to spend the entire day waiting for them.

Skyline used low-resolution satellite imagery to show the mountain terrain across France, Germany, and Switzerland. But for the race's final stage, which looped 55 kilometers (about 34 miles) around Paris before commencing under the Eiffel Tower, the company provided very high resolution (one-foot) aerial imaging data. "It made for an especially picturesque finish," says Katz. For this final stage, the group modeled 3D images of such landmarks as the Eiffel Tower, modeled in Discreet's (Montreal) 3D Studio Max.

The 3D terrain images from the Tour de France are just one section of what Katz refers to as the company's "digital Earth," which includes locations "of particular interest" throughout the world that Skyline is constructing in extremely high resolution. The key to the 3D environments are aerial photographs and new, high-quality commercial imaging satellite data, which are combined in a 3D terrain model constructed using the company's proprietary TerraBuilder application.

Skyline then converts the images within the database-measured in gigabytes and, in some cases, terabytes-into a real-time 3D streaming format using its TerraGate program. (A 56k modem is sufficient for viewing the data.) Lastly, the information is viewed as a 3D image through TerraPhoto3D or interactively with TerraExplorer.

"This technology basically has no limitations in the size of the database or the resolution," says Ronnie Yaron, Skyline co founder. "It's just a matter of collecting the data and building the databases."

The massive amount of data, like the other Terra applications, runs on NT servers housed at Skyline. The technology is scalable, he points out, so that the company can add as many servers as necessary to support the number of users flying over the terrain. During the first two weeks of providing the Tour de France coverage, Skyline logged more than 160,000 user sessions and provided more than a million TerraPhoto3D images, and is awaiting final statistics for the race's dynamic last stages.
For the final stage of the race, Skyline created a detailed flythrough model of Paris that included 3D Studio Max models of the city's famous landmarks.

The terrain for the Tour de France was actually part of a larger database-nearly the entire Earth-enabling the team to create the 3D imagery for the race in a few days, says Yaron. "It was just a matter of populating the 3D terrain with elements such as a line representing the roadway and points of interest along the route such as starting points, sites where provisions were provided to the racers, and high-level points that indicated the most difficult terrain." These enhancements were made using the company's TerraExplorer Pro tool.

By year end, Yaron expects to have every major US city included within the company's database. "If you're in the process of buying a house, you can see the neighborhood," he says, "or if you're traveling, you can see the location of your hotel." In the next few years, Yaron expects to have most locations entered into the database, during which time he expects the amount of data to reach hundreds of terabytes.

"In the past, the type of 3D flythrough used for the Tour de France was available only to high-end military customers. "We have taken elements of that concept and basically brought the ability down to a PC level for users at home," he says.

According to Yaron, using the Terra applications provides Internet users with a new way to look at the world and sporting events such as the Tour de France, where spectators could track competitors' progress over an extremely long course.

"The world is in color and 3D, yet all the information content that you're able to access on the Internet is shown with words, 2D pictures, or jerky videos," Yaron says. "We created a geographic 'world' browser that allows you to cruise over the Earth at any altitude and speed, and stop and look at things that interest you."

Terra product line, Skyline Software Systems (
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