I am using interpolate.interp1d and interpolate.rbf and could simplify my scripts greatly if I could get the original axes values from the interpolating function like f = interpolate.interp1d(x, y) and than somewhere else original_x = f.get_original_x() Is there such a thing as "get_original_x" Or if not possible is there at least a way to find the range of the axes to prevent extrapolation errors. I had a look at f.nodes but with no success My scipy is 0.9.0 Many thanks, Janwillem