Does anyone have any suggestions for good open source plotting software which has good graphical spherical coordinate plotting (from a data file). I have a three column data file where column 1 is $\theta$, column 2 is $\phi$ and column three is $f(\theta, \phi)$. I would like to plot this in spherical coordinates $(\theta, \phi, \rho = f(\theta, \phi))$, where points of equal $\rho$ are represented by equivalent colours. Does anyone have any recommendations regarding this type of plotting?
Also, is it possible to easily represent the plot with different colours as a function of the spherical coordinate $\rho$ (hence distance from the origin)?
By the way I used Python to produce these data files.