[R] Test for Random Points on a Sphere

[cberry at tajo.ucsd.edu]

"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