How to do it...

The following code block draws two plots, one with centimeters and the other with inches, to demonstrate the difference between two units of measurement:

1. Define a figure with two plots in a row:

fig, ax = plt.subplots(1,2)

2. Define line and the text artists to be added to the first axis:

line = lines.Line2D([0*cm, 1.5*cm], [0*cm, 2.5*cm], lw=2, 
                     color='black', axes=ax[0])
t = text.Text(3*cm, 2.5*cm, 'text label', ha='left', va='bottom', 
              axes=ax[0])

3. Add the artists to axis 0, and set the limits, units of measurement, and the grid:

ax[0].add_line(line)
ax[0].add_artist(t)
ax[0].set_xlim(-1*cm, 10*cm)
ax[0].set_ylim(-1*cm, 10*cm)
ax[0].xaxis.set_units(cm)
ax[0].yaxis.set_units(cm)
ax[0].grid(True)

4. Define the line and text artists to be added to the second axis:

line = lines.Line2D([0*cm, 1.5*cm], [0*cm, 2.5*cm], lw=2, 
                     color='black', axes=ax[1])
t = text.Text(3*cm, 2.5*cm, 'text label', ha='left', va='bottom', 
              axes=ax[1])

5. Add the artists to axes 1 and set limits, units of measurement, and grid:

ax[1].add_artist(line)
ax[1].add_artist(t)
ax[1].set_xlim(-1*cm, 10*cm)
ax[1].set_ylim(-1*cm, 10*cm)
ax[1].xaxis.set_units(inch)
ax[1].yaxis.set_units(inch)
ax[1].grid(True)

6. Set the title for the figure and adjust the space between the plots:

plt.suptitle("Demonstration of Units Of Measurement")
plt.tight_layout(pad=3)

7. Display the figure on the screen:

plt.show()