Rotation of axis labels¶

The angle parameter in element_text() function allows to rotate the text. This functionality is currently available to rotate axis labels (i.e. for the axis_text, axis_text_x, axis_text_y parameters in a theme()).

Default axis labels layout
Layout labels for the discrete axis
Layout labels for continuous axis

In [1]:

import pandas as pd

from lets_plot import *

In [2]:

LetsPlot.setup_html()
LetsPlot.set_theme(theme_light())

In [3]:

df = pd.read_csv('https://raw.githubusercontent.com/JetBrains/lets-plot-docs/master/data/midwest.csv')
df.head(3)

Out[3]:

	Unnamed: 0	PID	county	state	area	poptotal	popdensity	popwhite	popblack	popamerindian	...	percollege	percprof	poppovertyknown	percpovertyknown	percbelowpoverty	percchildbelowpovert	percadultpoverty	percelderlypoverty	category
0	1	561	ADAMS	IL	0.052	66090	1270.961540	63917	1702	98	...	19.631392	4.355859	63628	96.274777	13.151443	18.011717	11.009776	12.443812	AAR
1	2	562	ALEXANDER	IL	0.014	10626	759.000000	7054	3496	19	...	11.243308	2.870315	10529	99.087145	32.244278	45.826514	27.385647	25.228976	LHR
2	3	563	BOND	IL	0.022	14991	681.409091	14477	429	35	...	17.033819	4.488572	14235	94.956974	12.068844	14.036061	10.852090	12.697410	AAR

3 rows × 29 columns

In [4]:

df['state'].unique()

Out[4]:

array(['IL', 'IN', 'MI', 'OH', 'WI'], dtype=object)

In [5]:

df['state'] = df['state'].map(
    {'IL': 'Illinois', 'IN':'Indiana', 'MI':'Michigan', 'OH': 'Ohio', 'WI' : 'Wisconsin'}
)

In [6]:

def plot_matrix(plots=[], width=400, height=300, columns=2):
    bunch = GGBunch()
    for i in range(len(plots)):
        row = int(i / columns)
        column = i % columns
        bunch.add_plot(plots[i], column * width, row * height, width, height)
    return bunch.show()


angles = [0, 45, 90, -10]

highlight_axis_labels = theme(
    text=element_text(color='gray', size=13), 
    axis_text=element_text(color='blue')
)
    
def plot_with_text_angles(base_plot, text_elem_name):
    plots = []   
    for angle in angles:
        plots.append(
            base_plot + ggtitle("angle={0}".format(angle)) + theme(**{text_elem_name: element_text(angle=angle)})
        )
    return plot_matrix(plots)

1. Default Axis Labels Layout¶

In [7]:

p = ggplot(df) + geom_jitter(aes('state', 'poptotal'), color='light_gray', seed=42) + scale_y_log10()
p

Out[7]:

2. Layout labels for the discrete axis¶

Let's change rotation angle to check placement of labels on a discrete axis. Labels for the continuous will be disabled to avoid cluttering the plot.

Horizontal axis¶

In [8]:

plot_with_text_angles(
    p + theme(axis_text_y='blank') + highlight_axis_labels, 
    'axis_text_x'
)

In [9]:

# Change axis position

plot_with_text_angles(
    p + theme(axis_text_y='blank') + highlight_axis_labels + scale_x_discrete(position="top"), 
    'axis_text_x'
)

Vertical axis¶

When the rotation angle is set to 90°, some labels are not displayed to avoid overlapping.

In [10]:

plot_with_text_angles(
    p + theme(axis_text_y='blank') + highlight_axis_labels + coord_flip(),
    'axis_text_x'
)

In [11]:

# Change axis position

plot_with_text_angles(
    p + theme(axis_text_y='blank') + highlight_axis_labels + scale_x_discrete(position="top") + coord_flip(),
    'axis_text_x'
)

3. Layout labels for continuous axis¶

For continuous axis the number of labels varies depending on how many it can fit.

Horizontal axis¶

Changing the angle of rotation changes the number of labels on the axis: 90° rotation allows to place more labels on the horizontal axis.

In [12]:

plot_with_text_angles(
    p + theme(axis_text_x='blank') + highlight_axis_labels + coord_flip(),
    'axis_text_y'
)

In [13]:

# Change axis position

plot_with_text_angles(
    p + theme(axis_text_x='blank') + highlight_axis_labels + coord_flip() + scale_y_log10(position='right'),
    'axis_text_y'
)

Vertical axis¶

By changing the angle of rotation, thereby increasing the label heights, we get a reduction in the total number of labels on the vertical axis.

In [14]:

plot_with_text_angles(
    p + theme(axis_text_x='blank') + highlight_axis_labels,
    'axis_text_y'
)

In [15]:

# Change axis position

plot_with_text_angles(
    p + theme(axis_text_x='blank') + highlight_axis_labels + scale_y_log10(position='right'), 
    'axis_text_y'
)