Is there a way to rotate the ticklabels in a ternary plot with the python ternary package?

Question

I am working with the python ternary package. To improve the intuitive understanding of the plot, I want to rotate the tick labels on the axis to indicate in which direction the gridlines of this axis point, like in the plot below.

Python-ternary produces this result with the following code

from matplotlib import pyplot as plt
import ternary

figure, ax = plt.subplots(figsize=(6, 6))
tax = ternary.TernaryAxesSubplot(ax=ax, scale=100)

# draw Boundary and Gridlines
tax.boundary(linewidth=2.0)
tax.gridlines(color="black", multiple=10)

# ticks settings
tax.ticks(
    axis='lbr',
    linewidth=1,
    multiple=20,
    offset=0.02,
    fontsize=12
)

# remove mpl axes
tax.get_axes().axis('off')
tax.clear_matplotlib_ticks()
ternary.plt.show() 

what I have tried so far is

• tax.ticks(axis='b',rotation=45)
• tax.ticks(axis='b',labelrotation=45)
• tax.ticks(axis='b').set_rotation(45)

without success. any help is appreciated!

Answer 1

The cheap solution was of course just hack the tick labels in as annotations, which can be rotated with the rotation argument. not very elegant, but it solves the problem for now

from matplotlib import pyplot as plt
import ternary

fs = 16

figure, ax = plt.subplots(figsize=(6, 6))
tax = ternary.TernaryAxesSubplot(ax=ax, scale=100)

# draw Boundary and Gridlines
tax.boundary(linewidth=2.0)
tax.gridlines(color="black", multiple=10)

# define tick locations
tick_locs = range(10, 100, 10)

# add left ticks 
for i in tick_locs:
    tax.annotate(
        text=str(i),
        position=[-10, 100-i +2, 90],
        rotation=300,
        fontsize=fs
    )
    # add tick lines
    tax.line(
        [-3 , i+3, 90],
        [0 , i, 90],
        color='k'
    )
    
# add bottom ticks 
for i in tick_locs:
    tax.annotate(
        text=str(i),
        position=[i - 2, -10, 90],
        rotation=60,
        fontsize=fs
    )
    # add tick lines
    tax.line(
        [i , -3, 90],
        [i , 0, 90],
        color='k'
    )

# add right ticks
for i in tick_locs:
    tax.annotate(
        text=str(i),
        position=[105-i, i-2, 0],
        rotation=0,
        fontsize=fs
    )
    # add tick lines
    tax.line(
        [100-i , i, 0],
        [103-i , i, 0],
        color='k'
    )

# remove mpl axes
tax.clear_matplotlib_ticks()
ternary.plt.show()