diff --git a/src/c3nav/routing/graph/graph.py b/src/c3nav/routing/graph/graph.py
index 21fb1ecb..7d0095b3 100644
--- a/src/c3nav/routing/graph/graph.py
+++ b/src/c3nav/routing/graph/graph.py
@@ -10,6 +10,7 @@ from c3nav.routing.graph.connection import GraphConnection
 from c3nav.routing.graph.level import GraphLevel
 from c3nav.routing.graph.point import GraphPoint
 from c3nav.routing.graph.room import GraphRoom
+from c3nav.routing.graph.router import Router
 
 
 class Graph():
@@ -25,6 +26,9 @@ class Graph():
         self.rooms = []
         self.levelconnector_points = {}
 
+        self.transfer_points = []
+        self.router = Router()
+
     def build(self):
         for level in self.levels.values():
             level.build()
@@ -88,9 +92,16 @@ class Graph():
             graph = cls.unserialize(pickle.load(f))
         return graph
 
-    def draw_pngs(self, points=True, lines=True):
+    def build_router(self):
+        for room in self.rooms:
+            room.build_router()
+            self.transfer_points.extend(room.router.transfer_points)
+
+        self.router.build(self.transfer_points, global_routing=True)
+
+    def draw_pngs(self, points=True, lines=True, transfer_points=False, transfer_lines=False):
         for level in self.levels.values():
-            level.draw_png(points=points, lines=lines)
+            level.draw_png(points, lines, transfer_points, transfer_lines)
 
     def add_levelconnector_point(self, levelconnector, point):
         self.levelconnector_points.setdefault(levelconnector.name, []).append(point)
diff --git a/src/c3nav/routing/graph/level.py b/src/c3nav/routing/graph/level.py
index 8429dd77..18e85576 100644
--- a/src/c3nav/routing/graph/level.py
+++ b/src/c3nav/routing/graph/level.py
@@ -78,7 +78,7 @@ class GraphLevel():
         print('%d points' % len(self.points))
         print()
 
-    def draw_png(self, points=True, lines=True):
+    def draw_png(self, points=True, lines=True, transfer_points=False, transfer_lines=False):
         filename = os.path.join(settings.RENDER_ROOT, 'level-%s.base.png' % self.level.name)
         graph_filename = os.path.join(settings.RENDER_ROOT, 'level-%s.graph.png' % self.level.name)
 
@@ -94,4 +94,15 @@ class GraphLevel():
             for point in self.points:
                 draw.ellipse(_ellipse_bbox(point.x, point.y, height), (200, 0, 0))
 
+        if transfer_lines:
+            for point in self.points:
+                if point.in_room_transfer_distances is not None:
+                    for otherpoint, distance in point.in_room_transfer_distances.items():
+                        draw.line(_line_coords(point, otherpoint, height), fill=(100, 100, 255))
+
+        if transfer_points:
+            for point in self.points:
+                if point.in_room_transfer_distances is not None:
+                    draw.ellipse(_ellipse_bbox(point.x, point.y, height), (0, 0, 200))
+
         im.save(graph_filename)
diff --git a/src/c3nav/routing/graph/point.py b/src/c3nav/routing/graph/point.py
index e4fa6d21..61df89fe 100644
--- a/src/c3nav/routing/graph/point.py
+++ b/src/c3nav/routing/graph/point.py
@@ -10,6 +10,7 @@ class GraphPoint():
         self.xy = (x, y)
         self.connections = {}
         self.connections_in = {}
+        self.in_room_transfer_distances = None
 
     @cached_property
     def ellipse_bbox(self):
diff --git a/src/c3nav/routing/graph/room.py b/src/c3nav/routing/graph/room.py
index c704f6f8..a519f34b 100644
--- a/src/c3nav/routing/graph/room.py
+++ b/src/c3nav/routing/graph/room.py
@@ -6,6 +6,7 @@ from shapely.geometry import JOIN_STYLE, LineString
 
 from c3nav.mapdata.utils import assert_multipolygon
 from c3nav.routing.graph.point import GraphPoint
+from c3nav.routing.graph.router import Router
 from c3nav.routing.utils.coords import get_coords_angles
 from c3nav.routing.utils.mpl import polygon_to_mpl_paths
 
@@ -19,6 +20,8 @@ class GraphRoom():
         self.clear_geometry = geometry.buffer(-0.3, join_style=JOIN_STYLE.mitre)
         self.empty = self.clear_geometry.is_empty
 
+        self.router = Router()
+
         if mpl_paths is not None:
             self.mpl_paths = mpl_paths
         elif not self.empty:
@@ -63,6 +66,10 @@ class GraphRoom():
             for from_point, to_point in permutations(points, 2):
                 from_point.connect_to(to_point)
 
+    # noinspection PyTypeChecker
+    def build_router(self):
+        self.router.build(self.points)
+
     def _add_ring(self, geom, want_left):
         """
         add the points of a ring, but only those that have a specific direction change.
diff --git a/src/c3nav/routing/graph/router.py b/src/c3nav/routing/graph/router.py
new file mode 100644
index 00000000..e4678d23
--- /dev/null
+++ b/src/c3nav/routing/graph/router.py
@@ -0,0 +1,52 @@
+import numpy as np
+from scipy.sparse import csr_matrix
+from scipy.sparse.csgraph import shortest_path
+
+
+class Router():
+    def __init__(self):
+        self.points = []
+        self.points_pk = None
+
+        self.transfer_points = set()
+        self.shortest_paths = None
+        self.predecessors = None
+
+        self._built = False
+
+    # noinspection PyTypeChecker
+    def build(self, points, global_routing=False):
+        if self._built:
+            raise RuntimeError('already built.')
+        self._built = True
+
+        self.points = points
+        self.points_pk = dict(zip(self.points, range(len(self.points))))
+        matrix = np.zeros((len(self.points), len(self.points)))
+
+        for point, pk in self.points_pk.items():
+            for to_point, connection in point.connections.items():
+                if to_point not in self.points_pk:
+                    if not global_routing:
+                        self.transfer_points.add(point)
+                    continue
+                matrix[pk, self.points_pk[to_point]] = 1
+            if global_routing:
+                for to_point, distance in point.in_room_transfer_distances.items():
+                    matrix[pk, self.points_pk[to_point]] = distance
+
+        g_sparse = csr_matrix(np.ma.masked_values(np.fromstring(matrix).reshape(matrix.shape), 0))
+        self.shortest_paths, self.predecessors = shortest_path(g_sparse, return_predecessors=True)
+
+        if not global_routing:
+            for from_point in self.transfer_points:
+                from_point.in_room_transfer_distances = {}
+                connections = self.shortest_paths[self.points_pk[from_point], ]
+                for to_point_pk in np.argwhere(connections != np.inf).flatten():
+                    to_point = self.points[to_point_pk]
+                    if to_point not in self.transfer_points:
+                        continue
+                    from_point.in_room_transfer_distances[to_point] = connections[to_point_pk]
+
+    def get_distance(self, from_point, to_point):
+        return self.shortest_paths[self.points_pk[from_point], self.points_pk[from_point]]
diff --git a/src/c3nav/routing/management/commands/drawgraph.py b/src/c3nav/routing/management/commands/drawgraph.py
index eef67bf1..07cb599d 100644
--- a/src/c3nav/routing/management/commands/drawgraph.py
+++ b/src/c3nav/routing/management/commands/drawgraph.py
@@ -13,6 +13,15 @@ class Command(BaseCommand):
         parser.add_argument('--no-lines', action='store_const', dest='lines', const=False, default=True,
                             help='dont draw lines on the graph image')
 
+        parser.add_argument('--transfer-points', action='store_const', const=True, default=False,
+                            help='highlight transfer points')
+
+        parser.add_argument('--transfer-lines', action='store_const', const=True, default=False,
+                            help='draw in-room transfer lines')
+
     def handle(self, *args, **options):
         graph = Graph.load()
-        graph.draw_pngs(points=options['points'], lines=options['lines'])
+        if options['transfer_points'] or options['transfer_lines']:
+            graph.build_router()
+        graph.draw_pngs(points=options['points'], lines=options['lines'],
+                        transfer_points=options['transfer_points'], transfer_lines=options['transfer_lines'])
diff --git a/src/c3nav/routing/management/commands/testgraph.py b/src/c3nav/routing/management/commands/testgraph.py
new file mode 100644
index 00000000..795a68a7
--- /dev/null
+++ b/src/c3nav/routing/management/commands/testgraph.py
@@ -0,0 +1,19 @@
+import time
+
+from django.core.management.base import BaseCommand
+
+from c3nav.routing.graph import Graph
+
+
+class Command(BaseCommand):
+    help = 'check how long it takes to build the routers for the routing graph'
+
+    def handle(self, *args, **options):
+        start = time.time()
+        graph = Graph.load()
+        print('Graph loaded in %.4fs' % (time.time() - start))
+
+        start = time.time()
+        graph.build_router()
+        print('Routers built in %.4fs' % (time.time() - start))
+        print('%s transfer points' % len(graph.transfer_points))
diff --git a/src/requirements/production.txt b/src/requirements/production.txt
index 414057fb..5e296e04 100644
--- a/src/requirements/production.txt
+++ b/src/requirements/production.txt
@@ -9,3 +9,4 @@ celery>=3.1,<3.2
 requests>=2.11,<2.12
 Pillow>=3.4.2,<3.5
 matplotlib>=1.5.3,<1.6
+scipy>=0.18.1,<0.19