Problem with read_shp() in NetworkX

Question

I'm trying to convert a shapefile of only line geometry (a street network) to a NetworkX graph to run some connectivity algorithms on it. I'm running into this issue:

File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-    
packages/networkx/readwrite/nx_shp.py", line 69, in read_shp
for lyr in shp:
TypeError: 'NoneType' object is not iterable

It seems to be an issue with the ogr module the fcn requires, but I believe (?) I downloaded it, and it doesn't raise the exception error written in the source code. Any ideas?

EDIT: here's my code snippet: import networkx as nx

print 'nx imported'
G=nx.DiGraph()
G=nx.read_shp('shpfile.shp', \
              simplify = False)
print "running fine"

It gets stuck at the read_shp() and doesn't run the print command at the end to confirm it's running correctly.

Answer 1

It seem to me that you don't understand the principles of Nextwokx (see nx_spatial does not read all shapefile features)

Networkx generate a networkx.DiGraph from the shapefile, with nodes and edges and only these nodes and edges are iterables, not the Graph

import networkx as nx
G = nx.read_shp('mylines.shp')
print(G.nodes())
[(1.0, 2.0), (3.0, 2.0), (0.0, 0.0), (3.0, 1.0), (4.0, 4.0), (2.0, 1.0), (2.0, 4.0), (1.0, 3.0), (2.0, 3.0), (1.0, 4.0), (4.0, 3.0), (4.0, 2.0), (3.0, 4.0), (1.0, 1.0)]
print(G.edges())
[((1.0, 2.0), (1.0, 1.0)), ((3.0, 2.0), (2.0, 1.0)), ((3.0, 1.0), (2.0, 1.0)), ((4.0, 4.0), (3.0, 4.0)), ((2.0, 1.0), (1.0, 1.0)), ((2.0, 4.0), (2.0, 3.0)), ((1.0, 3.0), (1.0, 2.0)), ((2.0, 3.0), (1.0, 2.0)), ((1.0, 4.0), (1.0, 3.0)), ((4.0, 3.0), (4.0, 2.0)), ((4.0, 2.0), (3.0, 2.0)), ((3.0, 4.0), (2.0, 3.0)), ((1.0, 1.0), (0.0, 0.0))]

Therefore, the error for lyr in shp TypeError: 'NoneType' object is not iterable is normal.

But you don't need to browse anything, use directly the resulting DiGraph