### Navigation

- index
- modules |
- home|
- examples|
- tutorials|
- pyplot|
- docs »

# Triinterp Demo

Interpolation from triangular grid to quad grid.

    import matplotlib.pyplot as plt
    import matplotlib.tri as mtri
    import numpy as np

    # Create triangulation.
    x = np.asarray([0, 1, 2, 3, 0.5, 1.5, 2.5, 1, 2, 1.5])
    y = np.asarray([0, 0, 0, 0, 1.0, 1.0, 1.0, 2, 2, 3.0])
    triangles = [[0, 1, 4], [1, 2, 5], [2, 3, 6], [1, 5, 4], [2, 6, 5], [4, 5, 7],
                 [5, 6, 8], [5, 8, 7], [7, 8, 9]]
    triang = mtri.Triangulation(x, y, triangles)

    # Interpolate to regularly-spaced quad grid.
    z = np.cos(1.5 * x) * np.cos(1.5 * y)
    xi, yi = np.meshgrid(np.linspace(0, 3, 20), np.linspace(0, 3, 20))

    interp_lin = mtri.LinearTriInterpolator(triang, z)
    zi_lin = interp_lin(xi, yi)

    interp_cubic_geom = mtri.CubicTriInterpolator(triang, z, kind='geom')
    zi_cubic_geom = interp_cubic_geom(xi, yi)

    interp_cubic_min_E = mtri.CubicTriInterpolator(triang, z, kind='min_E')
    zi_cubic_min_E = interp_cubic_min_E(xi, yi)

    # Plot the triangulation.
    plt.subplot(221)
    plt.tricontourf(triang, z)
    plt.triplot(triang, 'ko-')
    plt.title('Triangular grid')

    # Plot linear interpolation to quad grid.
    plt.subplot(222)
    plt.contourf(xi, yi, zi_lin)
    plt.plot(xi, yi, 'k-', lw=0.5, alpha=0.5)
    plt.plot(xi.T, yi.T, 'k-', lw=0.5, alpha=0.5)
    plt.title("Linear interpolation")

    # Plot cubic interpolation to quad grid, kind=geom
    plt.subplot(223)
    plt.contourf(xi, yi, zi_cubic_geom)
    plt.plot(xi, yi, 'k-', lw=0.5, alpha=0.5)
    plt.plot(xi.T, yi.T, 'k-', lw=0.5, alpha=0.5)
    plt.title("Cubic interpolation,\nkind='geom'")

    # Plot cubic interpolation to quad grid, kind=min_E
    plt.subplot(224)
    plt.contourf(xi, yi, zi_cubic_min_E)
    plt.plot(xi, yi, 'k-', lw=0.5, alpha=0.5)
    plt.plot(xi.T, yi.T, 'k-', lw=0.5, alpha=0.5)
    plt.title("Cubic interpolation,\nkind='min_E'")

    plt.tight_layout()
    plt.show()

Total running time of the script: ( 0 minutes 0.353 seconds)

Generated by Sphinx-Gallery