 mvoelske -4 years ago 201
Python Question

# Matplotlib: draw lines with width given in data coordinates

I'm trying to figure out how to draw lines with widths in data units. For example, in the following code snippet, I would want the horizontal part of the line of width 80 to always extend from the y=-40 to the y=+40 mark, and stay that way even if the limits of the coordinate system change. Is there a way to achieve this with Line2D objects in matplotlib? Any other way to get a similar effect?

``````from pylab import figure, gca, Line2D

figure()
ax = gca()
ax.set_xlim(-50, 50)
ax.set_ylim(-75, 75)

ax.add_line(Line2D([-50, 0, 50], [-50, 0, 0], linewidth=80))

ax.grid()
``````  unutbu

You could use fill_between:

``````import matplotlib.pyplot as plt
import numpy as np

fig = plt.figure()
ax.set_xlim(-50, 50)
ax.set_ylim(-75, 75)
x = [-50, 0, 50]
y = np.array([-50, 0, 0])

ax.fill_between(x,y-30,y+30)

ax.grid()
plt.show()
``````

yields but unlike the line generated by

``````ax.add_line(Line2D([-50, 0, 50], [-50, 0, 0], linewidth=80))
``````

the vertical thickness of the line will always be constant in data coordinates.