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Hi. I’m Cindy Starr.At NASA’s Scientific Visualization

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Studio we work with many Earth science

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datasets that must be accurately positioned on a globe.

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For example, we obtained 30-meter topography data for Greenland

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along with an ocean and an ice sheet mask from the Greenland Ice

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Mapping Project at Ohio State. Each of these datasets

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consists of a 6 x 6 array of 124

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megapixel tiles. We also received seven sets of 20-meter

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Radarsat data from the Canadian Space Agency,

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mosaicked at the University of Washington‘s Applied Physics Lab.

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Each set consist of a 5 x 5 array of

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421 megapixel tiles. We developed

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an IDL routine that extracts the coordinate and projection

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information from geo-tif images and writes out RSL

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include files ^ that pass the parameters to a projection routine.

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The projection routine is a C++ Renderman plugin

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that computes the projection calculations in double precision

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and accurately positions the related texture tile.

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Parameters to the projection plugin are passed in string format in order to

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provide double precision accuracy. We employed this method with

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the high-resolution Greenland data, accurately mapping 87

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gigapixels of data.