Here is my solution:
http://martinus.geekisp.com/files/geodesic.zip
unzip and start depthcue.rb for a simple opengl visualization.

geodesic.rb contains the subsampling code,
geodesic-data.rb contains the data as published in the quiz, and
depthcue.rb is a simple opengl visualization (a modified opengl
sample).

This quiz was real fun to solve :-)

martinus