diff --git a/hub/helpers/geometry_helper.py b/hub/helpers/geometry_helper.py
index fc9d6a7a..d650eefd 100644
--- a/hub/helpers/geometry_helper.py
+++ b/hub/helpers/geometry_helper.py
@@ -64,15 +64,25 @@ class GeometryHelper:
 
   @staticmethod
   def city_mapping(city, building_names=None, plot=False):
+    """
+    Returns a shared_information dictionary like
+
+    {
+     "building_name" : [{line: 0 coordinate_1: [x,y,z], coordinate_2:[x, y, z], points: 0}]
+    }
+    """
+    shared_information = {}
     if building_names is None:
       building_names = [b.name for b in city.buildings]
     x = int((city.upper_corner[0] - city.lower_corner[0]) * 0.5) + 1
     y = int((city.upper_corner[1] - city.lower_corner[1]) * 0.5) + 1
-    city_map = [['' for _ in range(y + 1)] for _ in range(x + 1)]
+    city_map = [[{} for _ in range(y + 1)] for _ in range(x + 1)]
     img = Image.new('RGB', (x + 1, y + 1), "black")  # create a new black image
     city_image = img.load()  # create the pixel map
     for building_name in building_names:
       building = city.city_object(building_name)
+      shared_information[building_name]: []
+      line = 0
       for ground in building.grounds:
         length = len(ground.perimeter_polygon.coordinates) - 1
         for i, coordinate in enumerate(ground.perimeter_polygon.coordinates):
@@ -80,6 +90,8 @@ class GeometryHelper:
           if i == length:
             j = 0
           next_coordinate = ground.perimeter_polygon.coordinates[j]
+          line_dictionary = {"line": line, "coordinate_1": coordinate, "coordinate_2":next_coordinate, "points": 0}
+          print(line_dictionary)
           point = GeometryHelper.coordinate_to_map_point(coordinate, city)
           distance = GeometryHelper.distance_between_points(coordinate, next_coordinate)
           if distance == 0:
@@ -102,6 +114,7 @@ class GeometryHelper:
                 neighbour.neighbours = [building]
               elif building not in neighbour.neighbours:
                 neighbour.neighbours.append(building)
+          line += 1
     if plot:
       img.show()