How to Set Marker Size of Scatter Plot in Matplotlib
The size of markers in the scatter plot is controlled by s keyword argument of the function scatter(), where s is a scalar or an array.
s Keyword Argument of the Function Scatter()
Syntax for scatter function:
matplotlib.pyplot.scatter(x, y,
s=None,
c='b',
marker='o',
cmap=None,
norm=None,
vmin=None,
vmax=None,
alpha=None,
linewidths=None,
faceted=True,
verts=None,
hold=None,
**kwargs)
where, s is a scalar or an array of the same length as x and y, to set the markersize. The default marker size is rcParams['lines.markersize'] ** 2. According to documentation, s is the marker size in points**2.
Set the Same Marker Size of All Points
import numpy as np
import matplotlib.pyplot as plt
x = [1,2,3,4,5]
y=np.sin(x)
plt.scatter(x,y,s=500,c='magenta')
plt.title('Scatter plot of sinx')
plt.xlabel('x')
plt.ylabel('sinx')
plt.xlim(0,6)
plt.ylim(-2,2)
plt.show()
Increase Markersize of Points Non-Uniformly
Double the Width of Markers
To double the width (or height) of the marker we need to increase s by a factor of 4 as A = W*H => (2W)*(2H)= 4A.
import matplotlib.pyplot as plt
x = [1,2,3,4,5]
y = [a**2 for a in x]
s = [10*4**n for n in range(len(x))]
plt.scatter(x,y,s=s)
plt.title('Doubling width of marker in scatter plot')
plt.xlabel('x')
plt.ylabel('x**2')
plt.xlim(0,6)
plt.ylim(0,30)
plt.show()
Double the Area of Markers
To double the area of the marker, we increase the area by a factor of 2 so the marker size scales linearly with the area.
import matplotlib.pyplot as plt
x = [1,2,3,4,5]
y = [a**2 for a in x]
s = [10*2**n for n in range(len(x))]
plt.scatter(x,y,s=s)
plt.title('Doubling area of marker in scatter plot')
plt.xlabel('x')
plt.ylabel('x**2')
plt.xlim(0,6)
plt.ylim(0,30)
plt.show()
markersize Parameter to Control Size in plot Method
import matplotlib.pyplot as plt
x = [1,2,3,4,5]
y = [0]*len(x)
plt.plot(x,y, 'bo', markersize=10)
plt.show()
Here the area of circle is controlled by markersize parameter.
