How to uniformly sample the surface of a sphere?

Hi,

could someone help me to find a way of generating uniformly distributed samples over the surface of a sphere? I need something like 1400 sample over it. Moreover, I would like to obtain the spherical coordinates of each sample.

Thank you :)

Answer 1

[Bruno Luong]

There are few methods avialable on File exchange such as this one.

[Davide Mori]

I've already seen that, but it doesn't allow me to add the number of samples I want

[Bruno Luong]

You must then explain why N input argument is not suitable for your need.

function [V,Tri]=SpiralSampleSphere(N,vis)
% Produce an approximately uniform distribution of points on a unit sphere
% by sampling along a spherical spiral [1]. According to this approach 
% particle (i.e., sample) longitudes are proportional to particle rank 
% (1 to N) and latitudes are assigned to ensure uniform sampling density.  
%
% INPUT:
%   - N     : desired number of particles. N=200 is the default setting.
%             Note that sampling becomes more uniform with increasing N. 

[Davide Mori]

That's because I was using the function called

function [V,Tri,Ue_i,Ue]=ParticleSampleSphere(varargin)
% Generate an approximately uniform triangular tessellation of a unit 
% sphere by minimizing generalized electrostatic potential energy 
% (i.e., Reisz s-energy) of a system of charged particles. Effectively, 
% this function produces a locally optimal solution to the problem that 
% involves finding a minimum Reisz s-energy configuration of N equally 
% charged  particles confined to the surface of a unit sphere; s=1 
% corresponds to the problem originally posed by J.J. Thomson.

But Maybe I got confused by the alert that said "particle limit exceeded".

Anyway it seems like it returns the vertex of the sphere on both the functions, now I need to understand if I want to choose either one method or the other. What do you suggest?

[Bruno Luong]

I can't suggest anything relevant without knowing what you intend to do with the points.

Answer 2

[Gary Cofer]

For a realtime acqusition of data that can be cut short, a 3D Halton series works very well.