Test for Random Points on a Sphere
"Lorenzo Isella" <lorenzo.isella at gmail.com> writes:
Dear All, I implemented an algorithm for (uniform) random rotations. In order to test it, I can apply it to a unit vector (0,0,1) in Cartesian coordinates. The result is supposed to be a set of random, uniformly distributed, points on a sphere (not the point of the algorithm, but a way to test it). This is what the points look like when I plot them, but other then eyeballing them, can anyone suggest a test to ensure that I am really generating uniform random points on a sphere?
There is a substantial literature on this topic and more than one (metaphorical?) direction you could follow. I suggest you Google 'directional statistics' and start reading. Visit http://www.rseek.org and enter 'directional statistics' in the search box and click on the search button to see if there is something in R to meet your needs. A post to r-sig-geo might get more helpful responses once you can focus the question a bit more. HTH, Chuck
Many thanks Lorenzo
Charles C. Berry Dept of Family/Preventive Medicine cberry at ucsd edu UC San Diego http://famprevmed.ucsd.edu/faculty/cberry/ La Jolla, San Diego 92093-0901