How Virtual Yellowstone National Park in ScienceSim Was Made

Dr. Brian Quinn provided us with the data set for the terrain which was used to create virtual Yellowstone National Park in ScienceSim.   At the moment, the regions ‘just’ contain the terrain data, but even so, they’re compelling beautiful.  Exploring the regions is an interesting experience.

Comfortably seated in central heating, we can effortlessly fly through the ravines and canyons and over the lakes, while two thousand (or so) miles away, the real Yellowstone lays under a snow blanket. There’s just something indefinably special about knowing the terrain passing under our flying avatar is simulated real world terrain – and so much of it – and free – anyone can come in and fly around and look at it, explore it, hike over it.  It’s just there to be explored and wondered at.

And this is how it was made, according to Brian:

“First off – the source is USGS NED from seamless.usgs.gov, nominal 1/3 arc second sampling.  This stuff comes in in geographic (Lat/Long) coordinates, so it’s wildly distorted in east-west vs. north-south scales.  To resolve this, I projected the terrain to WGS84 UTM meters, and found that the resolution at Yellowtone’s latitude is about 7 meters.

Once both axes had a common scale, I clipped out a precise 85km square area with interesting terrain around the national park.  Then I made two realizations of OpenSim terrain.  For reference, my original 85km square consists of 12144 by 12144 single-precision float terrain samples.

Terrain set one is designed for the current 4×4 array of regions and is a 1:83 scale terrain with 1.5X Z-exaggeration for spice, with pedestal removed to bring lowest elevation near to 20 meters in Z.  It contains 16 ready-to-load f32 files.  Loading 16 of these by hand is simple enough to script.  The precise scale is (85000 / 1024)

Terrain set two is for deeper consideration, I also have prepared a nominal 1:10 scale Yellowstone with 1.5X z-exaggeration, with pedestal removed to just over 20 meters Z.  This data file has not been diced, although it has been flipped to accomodate the OpenSim bottum-up reading scheme.

This is a generic binary that is not tiled, as I don’t presently have code to generate the necessary scripts.  Expect 8192 by 8192 float32 values, starting from upper-left and finishing at lower-right in TV-raster scan style—BUT these are intended for regions starting in the lower-left and finishing in the upper-right. This file is intended to test seamless terrain loading into 1024 regions.  I’ve never had good success with the OpenSim “load tile” terrain, but because this source is square and a nice multiple of regions, I thought it might give the best chance to that function (if it’s still around) to work. The precise scale is (85000 / 8192)”

End quote.

And from Brian’s work, Mic Bowman, lead Intel researcher, loaded the terrain files onto the ScienceSim servers, and virtual Yellowstone emerged.  These images are shot from the Lake Shoshone region of the park.

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