High Resolution Tricontouring

#!/usr/bin/env python
"""
Demonstrates high-resolution tricontouring on user-defined triangular grids
with matplotlib.tri.UniformTriRefiner
"""
import matplotlib.tri as tri
import matplotlib.pyplot as plt
import matplotlib.cm as cm
import numpy as np
import math
from scipy.interpolate import griddata

data = np.genfromtxt('input.txt')
x = data[:,0]
y = data[:,1]
z = data[:,2]

# Now create the Triangulation.
# (Creating a Triangulation without specifying the triangles results in the
# Delaunay triangulation of the points.)
triang = tri.Triangulation(x, y)


#-----------------------------------------------------------------------------
# Refine data
#-----------------------------------------------------------------------------
refiner = tri.UniformTriRefiner(triang)
tri_refi, z_test_refi = refiner.refine_field(z, subdiv=3)

#-----------------------------------------------------------------------------
# Plot the triangulation and the high-res iso-contours
#-----------------------------------------------------------------------------
plt.figure()
plt.gca().set_aspect('equal')
plt.triplot(triang, lw=0.5, color='white')

levels = np.arange(-1200, -200, 10)  ##contour range
cmap = cm.get_cmap(name='terrain', lut=None)
plt.tricontourf(tri_refi, z_test_refi, levels=levels, cmap=cmap)
plt.tricontour(tri_refi, z_test_refi, levels=levels,
               colors=['0.25', '0.5', '0.5', '0.5', '0.5'],
               linewidths=[1.0, 0.5, 0.5, 0.5, 0.5])

plt.title("High-resolution tricontouring")

plt.show()