def endElement(self, name):
if name == 'node':
n = Vertex(id=self.id, pt=Point(self.geometry[0], self.geometry[1]))
n.save()
self.vertexs[self.id] = n
self.id = None
self.geometry = None
self.tags = None
def match_vertex(location):
""" Return the corresponding vertex for a given geometry. """
cursor = connection.cursor()
# Find the nearest edges for a given point
sql = (
"SELECT id, ST_Distance(GeomFromText('POINT(%s %s)',4326),line) AS myLineDistance FROM route_edge ORDER BY myLineDistance LIMIT 3;"
% (location.x, location.y)
)
cursor.execute(sql)
row = cursor.fetchone()
edge_id = row[0]
print "nearest road is ", Edge.objects.get(id=edge_id).name
# Find the closest point on the previous edge
sql = (
"SELECT AsText(ST_Line_Interpolate_Point(line,ST_Line_Locate_Point(line,GeomFromText('POINT(%s %s)', 4326)))) FROM route_edge WHERE id = %s;"
% (location.x, location.y, row[0])
)
cursor.execute(sql)
row = cursor.fetchone()
closestpt = row[0]
# Add this point to graph
id = (Vertex.objects.latest("id").id) + 1
print "id is ", id
v = Vertex(id=id, pt=closestpt)
v.save()
# Make edges connect to this point
e = Edge.objects.get(id=edge_id)
e_start = e.vertex_start
e_end = e.vertex_end
cost1 = distance(e_start.pt, v.pt)
e1 = Edge(
name=e.name,
cost=cost1,
reverse=e.reverse,
line=LineString([e_start.pt, v.pt]),
vertex_start=e_start,
vertex_end=v,
)
e1.save()
cost2 = distance(v.pt, e_end.pt)
e2 = Edge(
name=e.name, cost=cost2, reverse=e.reverse, line=LineString([v.pt, e_end.pt]), vertex_start=v, vertex_end=e_end
)
e2.save()
return v
