title: visualization of scattered data over a sphere surface MATLAB
body: <p>I wrote a 3D finite element code and I have the values of the function C(x,y,z) (FOUND in FEM) on a bunch of scattered data (x,y,z) over a surface of the sphere. I'm trying to visualize the function using <code>surf</code> on MATLAB and I already used <code>griddata</code> to interpolate the function C over the surface of a sphere, however it does not work and I face with the following problem:</p>
  
  <blockquote>
    <p>Warning: Duplicate x-y data points detected: using average of the z
    values</p>
  </blockquote>
  
  <p>and the ultimate figure I see at the end is just a poor section of sphere.</p>