nasa world wind from visualization to

NASA World Wind: from visualization to mission operations tool

Last Wednesday, Patrick Hogan, Project Manager of NASA World Wind,

spoke at Where 2.0 in San Jose. Hogan's fifteen-minute talk was a

straightforward description of the software, including comments on its

open-source nature, Earth and planetary visualization functionality,

and ongoing data import development. As Hogan spoke, World Wind

Designer Randy Kim demonstrated and drove the software. The most

newsworthy item was that World Wind has had 20 million downloads;

SourceForge numbers for World Wind list over 7.5 million in the past

year.

After the talk, I met NASA's Frank Kuehnel, Randy Kim, and Patrick

Hogan. During the conversation, I asked about a few details of World

Wind's architecture. First, while World Wind previously represented

Earth as a sphere, Kuehnel said that the next version, due this fall,

will be an ellipsoid. The team also has been working on a more

flexible tiling structure, using polyhedral segmentation. World Wind

tiles currently are composed of four-sided polygons. A major issue has

been that these tiles become pinched near the poles. As the four-sided

polygons approach the poles, the tiles effectively become triangles,

causing awkward image texture distortions. With the large number of

converging polygons, it also means that the geometry for the poles is

quite complex. Kuehnel said the complex geometry and distortions are

less problematic for Earth, since the poles are sparsely populated,

but that they pose a larger problem for other bodies. Undoubtedly, he

was referring to the fact that much of science on Mars and other

planets involves research near poles. World Wind's upcoming

architecture changes will minimize polar complexity and also allow the

mapping of nonspherical bodies--like asteroids and comets.

Other news:

* Also Wednesday at Where 2.0, Mark Lucas talked about OSSIM, a C++

open-source "high performance software system for remote sensing,

image processing, geographical information systems and

photogrammetry." As his closing slide, Lucas mentioned OSSIM's

virtual globe, osgPlanet. Ossim.org has a page describing this

virtual globe, including screenshots.

* As pointed out on Ogle Earth, Skyline Globe is not yet available

for download. Both the website and a SkylineGlobe developer said

the download will be available "shortly."

Image: A NASA World Wind 1.3.5 screenshot of the moon's southern