Streamplot

Draw dense vector flows with streamplot spacing, color by speed, and helpful start points.

import matplotlib.pyplot as plt
import numpy as np

import dartwork_mpl as dm

# Apply scientific style
dm.style.use("scientific")

# Generate vector field
Y, X = np.mgrid[-3:3:100j, -3:3:100j]
U = -1 - X**2 + Y
V = 1 + X - Y**2
speed = np.sqrt(U**2 + V**2)

fig = plt.figure(figsize=(dm.cm2in(10), dm.cm2in(8)), dpi=300)
gs = fig.add_gridspec(1, 1, left=0.12, right=0.88, top=0.92, bottom=0.12)
ax = fig.add_subplot(gs[0, 0])

# Streamplot
# Use dartwork-mpl's viridis colormap
strm = ax.streamplot(X, Y, U, V, color=speed, linewidth=2, cmap="dm.viridis")

# Add colorbar
cbar = fig.colorbar(strm.lines, ax=ax)
cbar.set_label("Speed", fontsize=dm.fs(0))

ax.set_title("Vector Field Streamplot", fontsize=dm.fs(1))
ax.set_xlabel("X Coordinate", fontsize=dm.fs(0))
ax.set_ylabel("Y Coordinate", fontsize=dm.fs(0))

dm.simple_layout(fig, gs=gs)
plt.show()