[NetworkX-discuss] TypeError while trying to draw_networkx_nodes
Tim Condit
I'm brand new to the list, but may be making regular appearances over the next few months. :)
I am using NetworkX and TIGER/Line data from the U.S. Census as the basis of a route finding project. I'm querying for longitude/latitude data, and want to plot a series of points (nodes). The result set from SQLAlchemy is a dict, keyed off the field names. It looks like this:
results=getrp(zipcode)
for result in results:
print "result.items:",result.items()
=> result.items: [('tlid', 186700174L), ('frlong', -122299134L), ('frlat', 47464521L), ('tolong', -122298734L), ('tolat', 47459721L)]
That's a TIGER/Line ID, from longitude, from latitude, to longitude, to latitude.
I just want to plot each pair of points, and the edges (representing street segments), so I can visualize my work. Am I going about it the right way? Or is there an easier way? I've tried a number of things, and feel like I'm missing something. Suggestions are gratefully accepted.
The code below results in this error:
timc@kitsap:~/agents/sandbox/learning$ python m.py
Traceback (most recent call last):
File "m.py", line 45, in ?
NX.draw_networkx_nodes(G,G.pos[to_tlid],node_size=12,node_color='g')
File "build/bdist.linux-i686/egg/networkx/drawing/nx_pylab.py", line 201, in draw_networkx_nodes
TypeError: tuple indices must be integers
####
import networkx as NX
import sqlalchemy as sql
# Set up database connection.
db=sql.create_engine("mysql://readonly:readonly@kitsap/agents")
metadata=sql.BoundMetaData(db)
# Tables are already created. Just load the existing schema.
rt1=sql.Table('tiger_01', metadata, autoload=True)
zipcode=98158
def getrp(zipcode):
'''Fetch and return a SQLAlchemy ResultProxy.'''
# Do the SELECT based on ZIPL for now...
results=sql.select([rt1.c.TLID,
rt1.c.FRLONG,
rt1.c.FRLAT,
rt1.c.TOLONG,
rt1.c.TOLAT,
],rt1.c.ZIPL==zipcode).execute()
return results
G=NX.XGraph(name='The %s zipcode area' % zipcode)
G.pos={}
results=getrp(zipcode)
#for result in results:
# print "result.items:",result.items()
for result in results:
fr_tlid='fr_'+str(result['tlid'])
frlong=result['frlong']
frlat=result['frlat']
to_tlid='to_'+str(result['tlid'])
tolong=result['tolong']
tolat=result['tolat']
G.add_node(fr_tlid)
G.add_node(to_tlid)
G.pos[fr_tlid]=(frlong,frlat)
G.pos[to_tlid]=(tolong,tolat)
G.add_edge(fr_tlid,to_tlid)
NX.draw_networkx_nodes(G,G.pos[to_tlid],node_size=12,node_color='g')
NX.draw_networkx_edges(G,G.pos,width=0.3,edge_color='r')
####
And thanks for this terrific software!
Cheers,
Tim Condit
Aric Hagberg
The only thing I can see right off is the line
> NX.draw_networkx_nodes(G,G.pos[to_tlid],node_size=12,node_color='g')
which should probably be
NX.draw_networkx_nodes(G,G.pos,node_size=12,node_color='g')
(e.g. no key in the G.pos dictionary).
Aric
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