David Given wrote:

> I'm trying to render the moon, to scale. The USGS provide a detailed
> topographic map of the moon in the form of about 270000 points in the
> form of latitude, longitude and radius tuples. Are there any cunning
> tricks I can use that will help me render this?

one way to combine the data into a more managable format would
be to "paint" the radius values into an image at the coordinates
given by latitude and longitude, in effect defining a height
field in spherical coordinates.

Although spherical height_fields are not directly supported
you can load the the data as an image_map pigment with spherical
mapping and define a pigment function based on it.

You could then either render it as an isosurface or derive
a mesh from the pigment function in SDL. For the isosurface
method have a look at the second example on

   http://www.econym.demon.co.uk/isotut/pigment.htm

where you would replace F with your height function.

Alternatively, you could also try a simple blob with
270000 components. But parsing will be even slower than
with the mesh2 approach then.

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