How do I draw a grid onto a plot in Python?
PythonMatplotlibPython Problem Overview
I just finished writing code to make a plot using pylab in Python and now I would like to superimpose a grid of 10x10 onto the scatter plot. How do I do that?
My current code is the following:
x = numpy.arange(0, 1, 0.05)
y = numpy.power(x, 2)
fig = plt.figure()
ax = fig.gca()
ax.set_xticks(numpy.arange(0, 1, 0.1))
ax.set_yticks(numpy.arange(0, 1., 0.1))
plt.scatter(x, y)
plt.show()
And its output is:
What I would like is the following output:
EDIT: Added an exemple, based on Andrey Sobolev's answer
Python Solutions
Solution 1 - Python
You want to use pyplot.grid:
x = numpy.arange(0, 1, 0.05)
y = numpy.power(x, 2)
fig = plt.figure()
ax = fig.gca()
ax.set_xticks(numpy.arange(0, 1, 0.1))
ax.set_yticks(numpy.arange(0, 1., 0.1))
plt.scatter(x, y)
plt.grid()
plt.show()
ax.xaxis.grid and ax.yaxis.grid can control grid lines properties.
Solution 2 - Python
To show a grid line on every tick, add
plt.grid(True)
For example:
import matplotlib.pyplot as plt
points = [ (0, 10), (10, 20), (20, 40), (60, 100),]
x = list(map(lambda x: x[0], points))
y = list(map(lambda x: x[1], points))
plt.scatter(x, y)
plt.grid(True)
plt.show()
In addition, you might want to customize the styling (e.g. solid line instead of dashed line), add:
plt.rc('grid', linestyle="-", color='black')
For example:
import matplotlib.pyplot as plt
points = [ (0, 10), (10, 20), (20, 40), (60, 100),]
x = list(map(lambda x: x[0], points))
y = list(map(lambda x: x[1], points))
plt.rc('grid', linestyle="-", color='black')
plt.scatter(x, y)
plt.grid(True)
plt.show()
Solution 3 - Python
Using rcParams you can show grid very easily as follows
plt.rcParams['axes.facecolor'] = 'white'
plt.rcParams['axes.edgecolor'] = 'white'
plt.rcParams['axes.grid'] = True
plt.rcParams['grid.alpha'] = 1
plt.rcParams['grid.color'] = "#cccccc"
If grid is not showing even after changing these parameters then use
plt.grid(True)
before calling
plt.show()
Solution 4 - Python
Here is a small example how to add a matplotlib grid in Gtk3 with Python 2 (not working in Python 3):
#!/usr/bin/env python
#-*- coding: utf-8 -*-
import gi
gi.require_version('Gtk', '3.0')
from gi.repository import Gtk
from matplotlib.figure import Figure
from matplotlib.backends.backend_gtk3agg import FigureCanvasGTK3Agg as FigureCanvas
win = Gtk.Window()
win.connect("delete-event", Gtk.main_quit)
win.set_title("Embedding in GTK3")
f = Figure(figsize=(1, 1), dpi=100)
ax = f.add_subplot(111)
ax.grid()
canvas = FigureCanvas(f)
canvas.set_size_request(400, 400)
win.add(canvas)
win.show_all()
Gtk.main()
