Hi all,

This must have been done hundreds of times, but well... there's no harm done
in discussing it once again.

I'm interested in modelling a "realistic" shape of our planet. With this I
mean basically a sphere (or spheroid) with a surface displacement matching
elevation/relief data. So far so good, I have the sphere and I have the
elevation data (<http://www.ngdc.noaa.gov/mgg/global/global.html>), I don't
need more resolution, but I don't want much less either.

Now the question is how to put them together in POV-Ray. The most obvious
solution is an isosurface. I created a 16-bit PGM file, 21600x10801 pixels,
a spherical image map of this file (in a pigment, in a function), and then
an isosurface of an sphere plus this function's .hf component. This works
fine, everything's OK, but it's sloooow (especially if I want radiosity,
refractions, etc).

The other solution is creating a mesh out of this data. I tried using the
HF_Sphere macro, but I'm afraid I need much better resolution than
possible. The maximum resolution vector I could use was about <500,1000>
(larger dimensions gave parsing errors in shapes.inc), and I'd need
<10801,21600>. For a total vertex number larger than a few million, this
number is written in exponential notation, and I don't think the mesh2
parser likes that. Besides, I'm afraid the file created (if I want
HF_Sphere to write a file) would be really huge.

Any thoughts? Other solutions? Fixes for HF_Sphere?

-- 
light_source{9+9*x,1}camera{orthographic look_at(1-y)/4angle 30location
9/4-z*4}light_source{-9*z,1}union{box{.9-z.1+x clipped_by{plane{2+y-4*x
0}}}box{z-y-.1.1+z}box{-.1.1+x}box{.1z-.1}pigment{rgb<.8.2,1>}}//Jellby

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