convert graph edge weights to meters

DistrictHeatingNetworkCreator.py

@@ -4,6 +4,26 @@ from shapely.geometry import Polygon, Point, LineString
 import networkx as nx
 from typing import List, Tuple
 from rtree import index
+import math
+
+
+def haversine(lon1, lat1, lon2, lat2):
+    """
+    Calculate the great-circle distance between two points
+    on the Earth specified by their longitude and latitude.
+    """
+    R = 6371000  # Radius of the Earth in meters
+    phi1 = math.radians(lat1)
+    phi2 = math.radians(lat2)
+    delta_phi = math.radians(lat2 - lat1)
+    delta_lambda = math.radians(lon2 - lon1)
+
+    a = math.sin(delta_phi / 2.0) ** 2 + \
+        math.cos(phi1) * math.cos(phi2) * \
+        math.sin(delta_lambda / 2.0) ** 2
+
+    c = 2 * math.atan2(math.sqrt(a), math.sqrt(1 - a))
+    return R * c  # Output distance in meters
 
 
 class DistrictHeatingNetworkCreator:
@@ -29,7 +49,8 @@ class DistrictHeatingNetworkCreator:
         self._create_graph()
         self._create_mst()
         self._iteratively_remove_edges()
-        self.add_centroids_to_mst()  # Add centroids to the MST
+        self._add_centroids_to_mst()
+        self._convert_edge_weights_to_meters()
         return self.final_mst
 
     def _load_and_process_data(self):
@@ -217,7 +238,7 @@ class DistrictHeatingNetworkCreator:
             single_connection_street_nodes = find_single_connection_street_nodes(self.final_mst)
             self.final_mst_steps.append(list(self.final_mst.edges(data=True)))
 
-    def add_centroids_to_mst(self):
+    def _add_centroids_to_mst(self):
         """
         Add centroids to the final MST graph and connect them to their associated node on the graph.
         """
@@ -238,6 +259,16 @@ class DistrictHeatingNetworkCreator:
             if nearest_point:
                 self.final_mst.add_edge(centroid_tuple, nearest_point, weight=min_distance)
 
+    def _convert_edge_weights_to_meters(self):
+        """
+        Convert all edge weights in the final MST graph to meters using the Haversine formula.
+        """
+        for u, v, data in self.final_mst.edges(data=True):
+            lon1, lat1 = u
+            lon2, lat2 = v
+            distance = haversine(lon1, lat1, lon2, lat2)
+            self.final_mst[u][v]['weight'] = distance
+
     def plot_network_graph(self):
         """
         Plot the network graph using matplotlib and networkx.