# Looking for a program to draw scientific sketches

Does someone know a free program with which i can draw high quality figures for my scientific thesis. I want to draw similar figures like this example

Picture is from: E. Lucon Oscillateurs coupl ́es, d ́esordre et

Python + Matplotlib (possibly used from within Jupyter Notebooks) can generate that sort of diagram at publication quality and in publication suitable formats, all for free and on multiple platforms.

## Some Example Code

As starting point, it's not perfect, but you should be able to get the idea:

Cell 1

%matplotlib inline


Cell 2

import matplotlib.pyplot as plt
from matplotlib.patches import Arc, Arrow
import numpy as np
import itertools


Cell 3

def get_circle(x, y, r=1):
""" Get a cirlce with a specific position and radius"""
result = plt.Circle((x, y), r, color='k', fill=False)
return result

def rpoint(x, y, r, deg):
""" Get a point on a radius at deg degrees."""
x1 = x + r * np.sin(rang)
y1 = y + r * np.cos(rang)
return (x1, y1)

def radial(x, y, r=1, ang=0, style="-"):
""" Draw a radial from a given center to the radius and an angle in degrees."""
x1, y1 = rpoint(x, y, r, ang)
result = plt.Line2D([x,x1], [y,y1], color='k', linestyle=style)
return result

def add_arc(x, y, r=1, ang1=0, ang2=0):
sr = r * 0.75
x1, y1 = rpoint(x, y, sr, ang2)
x2, y2 = rpoint(x, y, sr, ang2+15)
arc = Arc([x, y], sr*2, sr*2, angle=-100, theta1=ang2, theta2=ang1)
return arc

def add_arrow(x, y, r=1, ang1=0, ang2=0):
sr = r * 0.75
x1, y1 = rpoint(x, y, sr, ang2)
x2, y2 = rpoint(x, y, sr, ang2+10)
arrow = Arrow(x2, y2, x1-x2, y1-y2, color='k', linewidth=0.25)
return arrow

def add_lables(x, y, r, ang1, ang2, n):
x1, y1 = rpoint(x, y, r*1.21, ang1)
x2, y2 = rpoint(x, y, r*1.1, ang2)
text1 = plt.text(x1, y1, rf'$\theta_{n}$')
text2 = plt.text(x2, y2, rf'$\omega_{n}$')



Cell 4

fig, ax = plt.subplots()

centx, centy = 120, 120
item_count = 6
step = 360/item_count
offset = step/2
item_angs = [offset+step*n for n in range(item_count)]
#print(item_angs)
itemxys = [rpoint(centx, centy, radius, item_angs[n]) for n in range(item_count)]
items = [(*p, item_angs[n], n) for n,p in enumerate(itemxys)]
#print(items)

for x, y, ang, n in items:

for xy1, xy2 in itertools.combinations(itemxys, 2):
ax.add_artist(plt.Line2D([xy1[0], xy2[0]], [xy1[1], xy2[1]], color='lightgrey', linestyle=':'))

ax.axes.get_xaxis().set_visible(False)
ax.axes.get_yaxis().set_visible(False)
ax.plot()
plt.savefig('demo.svg')
plt.savefig('demo.png')
plt.savefig('demo.pdf')


## Results in:

O.K I haven't varied the angles, the label offsets need more work, etc., but I think this is a good starting point. All of the information I used to get this far was either in the matplotlib manuals or examples.

The above code is available in a GitHub gist: https://gist.github.com/GadgetSteve/557b7c995a824af92f455f5f475948d5

• I am actually using jupyter notebook but i have no idea how draw such a diagram. Is there some sort of tutorial that explains how to draw such figures in matplotlib? Feb 29 '20 at 11:44
• @Miradius: I have added some example code and a link to a gist. Mar 1 '20 at 15:32
• Thx Steve! That looks really promising. I will try to workout the little details. Mar 2 '20 at 10:01