gistfile1.py

class PlanckUniversalColormap(Colormap):
    name = "planckuniv"
    def __init__(self, cmap):
        Colormap.__init__(self, "planckuniv-" + cmap.name, cmap.N)
        self.cmap = cmap
        self.N = self.cmap.N

    def __call__(self, xi, alpha=1.0, **kw):
        x = xi * (1e7+1e3) - 1e3
        yi = self.modsinh(x)
        # range 0-1
        yi = (yi + 3)/10.
        return self.cmap(yi, alpha)

    def modsinh(self, x):
        return np.log10(0.5*(x + np.sqrt(x**2 + 4)))