def __init__(self, shapefile, distance_metric=EUCLIDEAN_DISTANCE):
if issubclass(type(shapefile), basestring): #Path
self.shp = shp = pysal.open(shapefile, 'r')
else:
raise TypeError, "Expecting a string, shapefile should the path to shapefile"
if shp.type != pysal.cg.shapes.Chain:
raise ValueError, "Shapefile must contain polyline features"
self.dbf = dbf = pysal.open(shapefile[:-4] + '.dbf', 'r')
header = dbf.header
if (('FNODE' not in header) or ('TNODE' not in header)
or ('ONEWAY' not in header)):
raise ValueError, "DBF must contain: FNODE,TNODE,ONEWAY"
oneway = [{'F': False, 'T': True}[x] for x in dbf.by_col('ONEWAY')]
fnode = dbf.by_col('FNODE')
tnode = dbf.by_col('TNODE')
if distance_metric == EUCLIDEAN_DISTANCE:
lengths = [x.len for x in shp]
elif distance_metric == ARC_DISTANCE:
lengths = [x.arclen for x in shp]
else:
raise ValueError, "distance_metric must be either EUCLIDEAN_DISTANCE or ARC_DISTANCE"
self.lengths = lengths
if any(oneway):
G = networkx.MultiDiGraph()
#def isoneway(x):
# return x[-1]
#def isnotoneway(x):
# if(x[-1]):
# return False
# return True
#
#A = filter(isoneway,zip(fnode,tnode,oneway))
#B = filter(isnotoneway,zip(fnode,tnode,oneway))
#C = filter(isnotoneway,zip(tnode,fnode,oneway))
#G.add_edges_from(A)
#G.add_edges_from(B)
#G.add_edges_from(C)
else:
G = networkx.MultiGraph()
#zip(fnode,tnode))
self.G = G
shp.seek(0)
self._locator = Polyline_Shapefile_SegmentLocator(shp)
