Subbasins connectivity

#!/usr/bin/python

import pyodbc
from pydot import Edge, Dot

cnxn = pyodbc.connect('DRIVER={MDBTools};DBQ=project.mdb')
cursor = cnxn.cursor()
cursor.execute("select FROM_NODE, TO_NODE from Reach")
graph = Dot(graph_type='digraph')
graph.set_rankdir("LR")
row = cursor.fetchone()
while row:
    e = Edge( * [str(x) for x in row] )
    graph.add_edge(e)
    row = cursor.fetchone()

graph.write_png("links.png")