Manual ContourΒΆ

Example of displaying your own contour lines and polygons using ContourSet.

import matplotlib.pyplot as plt
from matplotlib.contour import ContourSet
import matplotlib.cm as cm

Contour lines for each level are a list/tuple of polygons.

lines0 = [[[0, 0], [0, 4]]]
lines1 = [[[2, 0], [1, 2], [1, 3]]]
lines2 = [[[3, 0], [3, 2]], [[3, 3], [3, 4]]]  # Note two lines.

Filled contours between two levels are also a list/tuple of polygons. Points can be ordered clockwise or anticlockwise.

filled01 = [[[0, 0], [0, 4], [1, 3], [1, 2], [2, 0]]]
filled12 = [[[2, 0], [3, 0], [3, 2], [1, 3], [1, 2]],   # Note two polygons.
            [[1, 4], [3, 4], [3, 3]]]
fig, ax = plt.subplots()

# Filled contours using filled=True.
cs = ContourSet(ax, [0, 1, 2], [filled01, filled12], filled=True, cmap=cm.bone)
cbar = fig.colorbar(cs)

# Contour lines (non-filled).
lines = ContourSet(
    ax, [0, 1, 2], [lines0, lines1, lines2], cmap=cm.cool, linewidths=3)
cbar.add_lines(lines)

ax.set(xlim=(-0.5, 3.5), ylim=(-0.5, 4.5),
       title='User-specified contours')
User-specified contours

Out:

[(-0.5, 3.5), (-0.5, 4.5), Text(0.5, 1.0, 'User-specified contours')]

Multiple filled contour lines can be specified in a single list of polygon vertices along with a list of vertex kinds (code types) as described in the Path class. This is particularly useful for polygons with holes. Here a code type of 1 is a MOVETO, and 2 is a LINETO.

fig, ax = plt.subplots()
filled01 = [[[0, 0], [3, 0], [3, 3], [0, 3], [1, 1], [1, 2], [2, 2], [2, 1]]]
kinds01 = [[1, 2, 2, 2, 1, 2, 2, 2]]
cs = ContourSet(ax, [0, 1], [filled01], [kinds01], filled=True)
cbar = fig.colorbar(cs)

ax.set(xlim=(-0.5, 3.5), ylim=(-0.5, 3.5),
       title='User specified filled contours with holes')

plt.show()
User specified filled contours with holes

Total running time of the script: ( 0 minutes 1.243 seconds)

Keywords: matplotlib code example, codex, python plot, pyplot Gallery generated by Sphinx-Gallery