turn off axis, keep ticks

问题

I am plotting an image using plt.imshow() using the seaborn add on....

from astropy.io import fits
import numpy as np
import matplotlib.pyplot as plt
import seaborn as sns

sns.set_style(style='white') #turn off grid

def plotter():
    mapy = np.zeros((100,100))
    pf = 2.8 #my physical pixel size
    areaX = mapy.shape[0]/2*pf # half of the area!
    areaY = mapy.shape[1]/2*pf # half of the area!
    cmapz ='Reds'
    fig = imshow(mapy,interpolation='spline16',origin='lower',cmap=cmapz,extent=[-areaX*pf,areaX*pf,-areaY*pf,areaY*pf])
    plt.grid(False)
    plt.show()

I now want to get rid off the ugly axis around my plot, but KEEP the ticks in place as they refer to the distance.
Everything I found and tried, e.g. plt.axis('off'), fig.axes.get_yaxis().set_visible(False), plt.tick_params(top='off', bottom='on', left='off', right='off', labelleft='on', labelbottom='on') etc. turns off both the axis AND the ticks.

回答1:

You may decide not to use seaborn and turn the axes spines invisible:

for d in ["left", "top", "bottom", "right"]:
    plt.gca().spines[d].set_visible(False)

import numpy as np
import matplotlib.pyplot as plt

mapy = np.random.rand(100,100)
pf = 2.8
areaX = mapy.shape[0]/2*pf # half of the area!
areaY = mapy.shape[1]/2*pf # half of the area!

fig = plt.imshow(mapy,interpolation='spline16',origin='lower',
                 cmap='Reds',extent=[-areaX*pf,areaX*pf,-areaY*pf,areaY*pf])
plt.grid(False)

for d in ["left", "top", "bottom", "right"]:
    plt.gca().spines[d].set_visible(False)

plt.show()

The same can be done, using rcParams,

s = {"axes.spines.left"   : False,
    "axes.spines.bottom" : False,
    "axes.spines.top"    : False,
    "axes.spines.right"  : False}
plt.rcParams.update(s)

import numpy as np
import matplotlib.pyplot as plt
s = {"axes.spines.left"   : False,
"axes.spines.bottom" : False,
"axes.spines.top"    : False,
"axes.spines.right"  : False}
plt.rcParams.update(s)

mapy = np.random.rand(100,100)
pf = 2.8
areaX = mapy.shape[0]/2*pf # half of the area!
areaY = mapy.shape[1]/2*pf # half of the area!

fig = plt.imshow(mapy,interpolation='spline16',origin='lower',
             cmap='Reds',extent=[-areaX*pf,areaX*pf,-areaY*pf,areaY*pf])
plt.grid(False)

plt.show()

Alternatively you can set the axes edgecolor to transparent.

plt.rcParams["axes.edgecolor"]=(1,1,1,0)

import numpy as np
import matplotlib.pyplot as plt
plt.rcParams["axes.edgecolor"]=(1,1,1,0)

mapy = np.random.rand(100,100)
pf = 2.8
areaX = mapy.shape[0]/2*pf # half of the area!
areaY = mapy.shape[1]/2*pf # half of the area!

fig = plt.imshow(mapy,interpolation='spline16',origin='lower',
             cmap='Reds',extent=[-areaX*pf,areaX*pf,-areaY*pf,areaY*pf])
plt.grid(False)

plt.show()

Or, if you want to use seaborn (and it's white-style), additionally reactivate the ticks using

plt.tick_params(axis="both", which="major", length=5)

import numpy as np
import matplotlib.pyplot as plt
import seaborn as sns

sns.set_style(style='white') #turn off grid

mapy = np.random.rand(100,100)
pf = 2.8
areaX = mapy.shape[0]/2*pf # half of the area!
areaY = mapy.shape[1]/2*pf # half of the area!

fig = plt.imshow(mapy,interpolation='spline16',origin='lower',
                 cmap='Reds',extent=[-areaX*pf,areaX*pf,-areaY*pf,areaY*pf])
plt.grid(False)

for d in ["left", "top", "bottom", "right"]:
    plt.gca().spines[d].set_visible(False)

plt.tick_params(axis="both", which="major", length=5)
plt.show()

As @mwaskom points out in the comments, Seaborn also offers sns.despine() to get rid of the spines, which you would then call like

sns.despine(left=True, top=True, bottom=True, right=True)

Note the double negation (despine True means not to have spines).

import numpy as np
import matplotlib.pyplot as plt
import seaborn as sns

sns.set_style(style='white') #turn off grid

mapy = np.random.rand(100,100)
pf = 2.8
areaX = mapy.shape[0]/2*pf # half of the area!
areaY = mapy.shape[1]/2*pf # half of the area!

fig = plt.imshow(mapy,interpolation='spline16',origin='lower',
             cmap='Reds',extent=[-areaX*pf,areaX*pf,-areaY*pf,areaY*pf])
plt.grid(False)
sns.despine(left=True, top=True, bottom=True, right=True)

plt.tick_params(axis="both", which="major", length=5)
plt.show()

来源：https://stackoverflow.com/questions/44525032/turn-off-axis-keep-ticks

标签

matplotlib

seaborn