Using networkX to output a tree structure

Question

I am using networkX to generate a tree structure as follows (I am following the answer of this question).

import networkx as nx
import matplotlib.pyplot as plt
G = nx.DiGraph()

G.add_node("ROOT")
for i in range(5):
    G.add_node("Child_%i" % i)
    G.add_node("Grandchild_%i" % i)
    G.add_node("Greatgrandchild_%i" % i)

    G.add_edge("ROOT", "Child_%i" % i)
    G.add_edge("Child_%i" % i, "Grandchild_%i" % i)
    G.add_edge("Grandchild_%i" % i, "Greatgrandchild_%i" % i)

# write dot file to use with graphviz
# run "dot -Tpng test.dot >test.png"
nx.write_dot(G,'test.dot')

# same layout using matplotlib with no labels
plt.title('draw_networkx')
pos=nx.graphviz_layout(G, prog='dot')
nx.draw(G, pos, with_labels=False, arrows=False)
plt.savefig('nx_test.png')

I want to draw a tree as in the following figure.

However, I am getting an error saying AttributeError: module 'networkx' has no attribute 'write_dot'. My networkx version is 1.11 (using conda). I tried different hacks, but none of them worked.

So, I am interested in knowing if there is another way of drawing tree structures using networkx to get an output similar to the one mentioned in the figure. Please let me know.

score 2 · Answer 1 · answered Jan 22 '18 at 17:08

2

I think this issue was solved on networkx 2.x, but before that you should be explicit import of the function like this.

from networkx.drawing.nx_agraph import write_dot

or

from networkx.drawing.nx_pydot import write_dot

I hope this works.

answered Jan 22 '18 at 17:08

Tzomas

704
5
17

Anil_M · Accepted Answer · 2018-01-22T18:46:09.843

You can draw digraph entirely with pygraphviz.

Following steps needs to be followed first as pygraphviz does not work without graphviz (as of now).

Download graphviz-2.38.msi from http://www.graphviz.org/Download_windows.php and install
Download the 2.7 or 3.4 pygraphviz wheel file from http://www.lfd.uci.edu/~gohlke/pythonlibs/#pygraphviz
Navigate to the directory that you downloaded the wheel file and run your platform specific wheel pip install pygraphviz‑1.3.1‑cp34‑none‑win32.whl
Add dot.exe to host path e.g. on windows control-panel ->system -> edit environment variables -> Modify PATH

After that dot and png files can be created as below.

Working Code

import pygraphviz as pgv

G=pgv.AGraph(directed=True)

#Attributes can be added when adding nodes or edge
G.add_node("ROOT", color='red')
for i in range(5):
    G.add_node("Child_%i" % i, color='blue')
    G.add_node("Grandchild_%i" % i, color='blue')
    G.add_node("Greatgrandchild_%i" % i, color='blue')

    G.add_edge("ROOT", "Child_%i" % i, color='blue')
    G.add_edge("Child_%i" % i, "Grandchild_%i" % i, color='blue')
    G.add_edge("Grandchild_%i" % i, "Greatgrandchild_%i" % i, color='blue')

# write to a dot file
G.write('test.dot')

#create a png file
G.layout(prog='dot') # use dot
G.draw('file.png')

PNG File

Using networkX to output a tree structure

2 Answers2