title: How can I interpolate array from spherical to cartesian coordinates with Python?
body: <p>I have an array of density values in spherical coordinates.  More specifically I have an array called density with shape (180,200,200).  I also have an array called r_coord, theta_coord and phi_coord also with shape (180,200,200) being the spherical coordinates for the density array.  </p>
  
  <p>I would like to map this density to cartesian coordinates using python.  I will need therefore a new density2 which is interpolated over cartesian coordinates x_coord, y_coord and z_coord.  I found scipy.ndimage.interpolation.map_coordinates which looks promising but I can't figure out how to get it to work.  </p>
  
  <p>Any help would be appreciated.  Thanks.   </p>