Griddata uses a spline fitting. A 3rd order spline is not the same thing as a 3rd order polynomial (instead, it’s a different 3rd order polynomial at every point). If you just want to fit a 2D, 3rd order polynomial to your data, then do something like the following to estimate the 16 coefficients using … Read more
Solution with matplotlib: #!/usr/bin/python3 import sys import matplotlib import matplotlib.pyplot as plt from matplotlib.ticker import MaxNLocator from matplotlib import cm from mpl_toolkits.mplot3d import Axes3D import numpy from numpy.random import randn from scipy import array, newaxis # ====== ## data: DATA = array([ [-0.807237702464, 0.904373229492, 111.428744443], [-0.802470821517, 0.832159465335, 98.572957317], [-0.801052795982, 0.744231916692, 86.485869328], [-0.802505546206, 0.642324228721, 75.279804677], [-0.804158144115, … Read more