NASA opens World Wind viewer as a mapping tool

Outside developers can embed NASA images and functions in their own geomapping applications

FLIGHT PLAN: Using World Wind, DiSTI was able to quickly put together this flight 3-D simulation package.

When Tom Gaskins presents NASA's World Wind satellite imagery viewer in a public forum, he usually hears the audience collectively catch its breath as the viewer switches from a standard view ' the geomapping perspective looking straight down at the surface of the Earth ' to a 3-D view that looks out over the imagery.

Such a view displays elevations and other contours of the land in a view similar to what you would see if you were there yourself.

Beyond flat images

'I think we're all used to static and flat images, but I liken what we can do now to the portraits in the Harry Potter books, where they can move and talk to you,' said Gaskins, technical director at World Wind, who spoke at the JavaOne conference in San Francisco.

Outside developers can use this awe-inspiring technology for their own geomapping programs.

The agency has released the World Wind Java Software Development Kit, a library of Java-based application programming interfaces (API) that can be used to embed live World Wind imagery and functions in other programs.

Although World Wind started as a 3-D viewer for satellite imagery (See, other programs such as Google Earth and Microsoft Virtual Earth have eclipsed the viewer in popularity in recent years.

As a result, NASA has changed its focus in offering World Wind. 'World Wind is a component, not an application,' Gaskins said. 'World Wind's role is to give a background for another application but otherwise stay out of the way.'

When run on its own, World Wind presents a user with an image of the Earth.

The user downloads a launcher from NASA servers and runs the entire program via the Internet. The user can zoom in on a particular area for more detailed photos, which the application stitches together to provide a continuous view. The software can also render the terrain in 3-D, allowing users to gauge elevations and contours.

When called from within the developer's Java program, the World Wind APIs can be used to automatically pull in, position and layer terrain imagery for the application's viewer. The idea is for developers to draw imagery from World Wind and then overlay their information on the photographs, Gaskins said.

One early user of the service is software tool vendor DiSTI. At JavaOne, that company's chief technology officer, Darren Humphrey, demonstrated a proof-of-concept flight simulation application that uses World Wind imagery as a backdrop. The company's flagship product, GL Studio, allows developers to build human/machine interfaces and simulation applications.

The proof-of-concept software mimics the cockpit of an F-16 aircraft, including live instrument panels.

As the user flies over terrain, World Wind automatically streams the appropriate imagery to the program. Humphrey showed the aircraft flying over desert and ice-covered terrain (for a trial run, go to

By using World Wind, the company cut development time of the application to three weeks, Humphrey said. JavaOne provided its own Java-based simulation program which meshed with features offered by WorldWind.

NASA provides some of the imagery and topological information, and third-party government and commercial sources, such as Microsoft Virtual Earth, provide the rest. As the viewer navigates to a particular location, NASA servers deliver the imagery on a just-in-time basis.

The first version of World Wind was written on a .NET platform. Last year, the project team retired that version and rewrote it from scratch using Java.

'We needed a cross-platform solution,' said Patrick Hogan, NASA World Wind project manager. Because it is written in Java, the program can run on most systems widely used today, including Microsoft Windows, Macintosh and Linux. With the .NET version, the team could only offer the application for Windows.

Java app assists

The application relies heavily on Java OpenGL API, or JOGL, which renders 3-D graphics.

World Wind is made up of a number of discrete components, such as a scene controller, frame controller and viewer window. The project team designed the software so each World Wind component can be easily replaced by the developer with something more sophisticated, Gaskins said.

Sun Microsystems helped fund the effort to develop this version of World Wind, and a myriad of others contributed time and monetary support. Volunteer contributors have rallied around World Wind Central (, an online repository of World Wind information. The Defense Department, the Energy Department's Sandia National Laboratories, NATO, the European Space Agency and the South African Space Agency have also aided the effort.

World Wind provides a conduit for NASA to get its data to more citizens, and eventually improve the quality of software the agency can purchase from the private sector.

'NASA World Wind technology increases the ability for NASA to share data, be it for research or government use,' Hogan said. 'It also helps to stimulate entrepreneurial enterprise in ways that greatly enhance the ability for the government to secure solutions for its myriad of information visualization needs.'

About the Author

Joab Jackson is the senior technology editor for Government Computer News.


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