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"""
==========
Wind barbs
==========
Demonstration of wind barb plots.
"""
import matplotlib.pyplot as plt
import numpy as np
x = np.linspace(-5, 5, 5)
X, Y = np.meshgrid(x, x)
U, V = 12 * X, 12 * Y
data = [(-1.5, .5, -6, -6),
(1, -1, -46, 46),
(-3, -1, 11, -11),
(1, 1.5, 80, 80),
(0.5, 0.25, 25, 15),
(-1.5, -0.5, -5, 40)]
data = np.array(data, dtype=[('x', np.float32), ('y', np.float32),
('u', np.float32), ('v', np.float32)])
fig1, axs1 = plt.subplots(nrows=2, ncols=2)
# Default parameters, uniform grid
axs1[0, 0].barbs(X, Y, U, V)
# Arbitrary set of vectors, make them longer and change the pivot point
# (point around which they're rotated) to be the middle
axs1[0, 1].barbs(
data['x'], data['y'], data['u'], data['v'], length=8, pivot='middle')
# Showing colormapping with uniform grid. Fill the circle for an empty barb,
# don't round the values, and change some of the size parameters
axs1[1, 0].barbs(
X, Y, U, V, np.sqrt(U ** 2 + V ** 2), fill_empty=True, rounding=False,
sizes=dict(emptybarb=0.25, spacing=0.2, height=0.3))
# Change colors as well as the increments for parts of the barbs
axs1[1, 1].barbs(data['x'], data['y'], data['u'], data['v'], flagcolor='r',
barbcolor=['b', 'g'], flip_barb=True,
barb_increments=dict(half=10, full=20, flag=100))
# Masked arrays are also supported
masked_u = np.ma.masked_array(data['u'])
masked_u[4] = 1000 # Bad value that should not be plotted when masked
masked_u[4] = np.ma.masked
# %%
# Identical plot to panel 2 in the first figure, but with the point at
# (0.5, 0.25) missing (masked)
fig2, ax2 = plt.subplots()
ax2.barbs(data['x'], data['y'], masked_u, data['v'], length=8, pivot='middle')
plt.show()
# %%
#
# .. admonition:: References
#
# The use of the following functions, methods, classes and modules is shown
# in this example:
#
# - `matplotlib.axes.Axes.barbs` / `matplotlib.pyplot.barbs`
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