plot_temperature.py

#!/usr/bin/env ipython
# -*- coding: utf-8 -*-

import sys
import vtk
import numpy as np
import matplotlib.pyplot as plt


def _read_data(filename):
    """Read data from time, return tuple of arrays x, y, T."""
    reader = vtk.vtkXMLImageDataReader()
    reader.SetFileName(filename)
    reader.Update()

    data = reader.GetOutput()
    temperature = data.GetPointData().GetArray(0)

    n = data.GetNumberOfPoints()

    x = np.zeros(n)
    y = np.zeros(n)
    T = np.zeros(n)

    for i in range(n):
        x[i] = data.GetPoint(i)[0]
        y[i] = data.GetPoint(i)[1]
        T[i] = temperature.GetValue(i)

    return x, y, T


def _plot():
    DATA_FILE = 'Case-1.vti'
    x, y, T = _read_data(DATA_FILE)

    plt.figure(figsize=(8, 8))
    plt.jet()
    plt.tricontourf(x, y, T, 64)
    plt.savefig('temperature.pdf', bbox_inches='tight', bbox_padding=0.5)

if __name__ == '__main__':
    sys.exit(_plot())

And result