Road Network Integration
Integrate real-world street networks from OpenStreetMap into your VRP toolkit using map data.
Integration Workflow
Step 1: Install Dependencies
Install OSMnx and geo-processing libraries.
Using conda (recommended):
conda install -c conda-forge osmnx
Using pip:
pip install osmnx geopandas shapely fiona pyproj
Verify installation:
import osmnx as ox print(f"OSMnx version: {ox.version}")
Troubleshooting: See troubleshooting.md for installation issues.
Step 2: Load Street Network
Choose loading method based on your needs:
Option A: Load by Place Name
For well-known locations (recommended for campuses, cities).
import osmnx as ox
Load area by name
place_name = "Purdue University, West Lafayette, IN, USA" G = ox.graph_from_place( place_name, network_type='drive', # 'drive', 'walk', 'bike', or 'all' simplify=True )
Save for reuse (much faster than re-downloading)
ox.save_graphml(G, "data/campus_network.graphml")
print(f"Loaded {len(G.nodes)} nodes and {len(G.edges)} edges")
Option B: Load by Bounding Box
For specific coordinate ranges.
Define bounding box (north, south, east, west)
north, south, east, west = 40.4300, 40.4200, -86.9100, -86.9250
G = ox.graph_from_bbox(north, south, east, west, network_type='drive')
Data structure details: See maintain-data-structures skill → data_layer.md → OSMnx Graph
More examples: See osmnx_examples.md → Examples 1-2
Step 3: Define VRP Locations
Map your problem locations (depot, customers, pickups, deliveries) to network nodes.
3a. Extract from Points of Interest (POIs)
Find buildings/amenities as potential locations
tags = { 'building': ['university', 'dormitory'], 'amenity': ['cafe', 'restaurant', 'library'] }
pois = ox.geometries_from_place(place_name, tags=tags)
Extract coordinates
locations = [] for idx, poi in pois.iterrows(): if poi.geometry.geom_type == 'Point': lat, lon = poi.geometry.y, poi.geometry.x else: # Polygon lat, lon = poi.geometry.centroid.y, poi.geometry.centroid.x
locations.append((lat, lon))
print(f"Found {len(locations)} potential customer locations")
3b. Use Manually Defined Locations
Define locations manually (lat, lon)
depot_loc = (40.4237, -86.9212)
pickup_locs = [ (40.4280, -86.9145), (40.4200, -86.9180) ]
delivery_locs = [ (40.4250, -86.9100), (40.4210, -86.9220) ]
More examples: See osmnx_examples.md → Example 3
Step 4: Map to Network Nodes
Find nearest nodes in the street network for each location.
Find nearest network nodes
depot_node = ox.distance.nearest_nodes( G, depot_loc[1], # X = longitude depot_loc[0] # Y = latitude )
pickup_nodes = [ ox.distance.nearest_nodes(G, lon, lat) for lat, lon in pickup_locs ]
delivery_nodes = [ ox.distance.nearest_nodes(G, lon, lat) for lat, lon in delivery_locs ]
All nodes for VRP instance
all_osm_nodes = [depot_node] + pickup_nodes + delivery_nodes
print(f"Mapped to {len(all_osm_nodes)} network nodes")
IMPORTANT: nearest_nodes takes (X, Y) which is (longitude, latitude) , NOT (lat, lon) !
Troubleshooting: See troubleshooting.md → Coordinate Issues
More examples: See osmnx_examples.md → Example 4
Step 5: Compute Distance Matrix
Calculate network-based distances between all nodes.
import networkx as nx import numpy as np
n = len(all_osm_nodes) distance_matrix = np.zeros((n, n))
for i, origin in enumerate(all_osm_nodes): # Compute shortest paths from origin to all destinations lengths = nx.single_source_dijkstra_path_length( G, origin, weight='length' # Use 'length' for distance in meters )
for j, dest in enumerate(all_osm_nodes):
if i != j and dest in lengths:
distance_matrix[i, j] = lengths[dest]
print("Distance matrix computed (in meters)") print(distance_matrix)
Optional: Convert to time matrix
average_speed_kmh = 30 # km/h average_speed_ms = average_speed_kmh * 1000 / 3600 # m/s
time_matrix_seconds = distance_matrix / average_speed_ms time_matrix_minutes = time_matrix_seconds / 60
Data structure details: See maintain-data-structures skill → runtime_formats.md → Distance Matrix
Troubleshooting: See troubleshooting.md → Routing Issues
More examples: See osmnx_examples.md → Examples 5-6
Step 6: Create Node Objects
Create VRP toolkit Node objects from OSMnx nodes.
from vrp_toolkit.problems import Node
nodes = []
Depot
depot_data = G.nodes[depot_node] nodes.append(Node( node_id=0, x=depot_data['x'], # longitude y=depot_data['y'], # latitude node_type='depot' ))
Pickups and deliveries (paired)
for idx, (p_node, d_node) in enumerate(zip(pickup_nodes, delivery_nodes), 1): pickup_id = idx * 2 - 1 delivery_id = idx * 2
# Pickup node
p_data = G.nodes[p_node]
nodes.append(Node(
node_id=pickup_id,
x=p_data['x'],
y=p_data['y'],
demand=10.0, # Adjust as needed
time_window=(8.0, 17.0), # 8am - 5pm
service_time=0.25, # 15 minutes
node_type='pickup',
pair_node_id=delivery_id
))
# Delivery node
d_data = G.nodes[d_node]
nodes.append(Node(
node_id=delivery_id,
x=d_data['x'],
y=d_data['y'],
demand=-10.0, # Negative for delivery
time_window=(8.0, 17.0),
service_time=0.25,
node_type='delivery',
pair_node_id=pickup_id
))
print(f"Created {len(nodes)} Node objects")
Data structure details: See maintain-data-structures skill → problem_layer.md → Node
Step 7: Create PDPTW Instance
Combine everything into a problem instance.
from vrp_toolkit.problems import PDPTWInstance
instance = PDPTWInstance( nodes=nodes, battery_capacity=100.0, max_route_time=480.0, # 8 hours in minutes vehicle_capacity=50.0 )
Attach distance matrix
instance.distance_matrix = distance_matrix
Optionally attach time matrix
instance.time_matrix = time_matrix_minutes
Save instance for later use
import pickle with open('data/campus_pdptw_instance.pkl', 'wb') as f: pickle.dump(instance, f)
print("PDPTW instance created successfully!")
Complete example: See osmnx_examples.md → Example 7
Data structure details: See maintain-data-structures skill → problem_layer.md → PDPTWInstance
Step 8: Validate and Solve
Test the instance and solve.
from vrp_toolkit.algorithms.alns import ALNSSolver, ALNSConfig
Validate instance
print(f"Number of nodes: {len(instance.nodes)}") print(f"Number of pickup-delivery pairs: {len(instance.pickup_delivery_pairs)}") print(f"Distance matrix shape: {instance.distance_matrix.shape}")
Solve
config = ALNSConfig(max_iterations=1000) solver = ALNSSolver(config) solution = solver.solve(instance)
Check solution
if solution.is_feasible(): print(f"Feasible solution found!") print(f"Objective value: {solution.objective_value()}") solution.plot() else: print("Solution is infeasible")
Advanced Features
Visualize Routes on Street Network
Plot solution routes on the actual map.
import matplotlib.pyplot as plt
Plot base network
fig, ax = ox.plot_graph( G, bgcolor='white', node_size=0, edge_color='gray', edge_linewidth=0.5, show=False, close=False )
Plot solution routes (assuming routes contain OSM node IDs)
colors = ['blue', 'red', 'green', 'orange']
for route_idx, route in enumerate(solution.routes): # Map VRP node IDs back to OSM node IDs osm_route = [all_osm_nodes[node_id] for node_id in route]
# Get coordinates
xs = [G.nodes[node]['x'] for node in osm_route]
ys = [G.nodes[node]['y'] for node in osm_route]
# Plot
ax.plot(xs, ys,
color=colors[route_idx % len(colors)],
linewidth=3,
alpha=0.7,
label=f'Route {route_idx + 1}')
ax.legend() plt.title("VRP Solution on Real Street Network") plt.show()
More examples: See osmnx_examples.md → Example 8
Cache for Performance
Save processed graphs to avoid re-downloading.
import os
cache_file = "data/campus_network.graphml"
if os.path.exists(cache_file): # Load from cache (instant!) G = ox.load_graphml(cache_file) print("Loaded from cache") else: # Download and save G = ox.graph_from_place(place_name) ox.save_graphml(G, cache_file) print("Downloaded and cached")
More examples: See osmnx_examples.md → Example 9
Handle Graph Connectivity
Ensure all nodes can reach each other.
import networkx as nx
Check connectivity
if not nx.is_weakly_connected(G): print("Graph has multiple disconnected components")
# Keep only largest connected component
largest_component = max(
nx.weakly_connected_components(G),
key=len
)
G = G.subgraph(largest_component).copy()
print(f"Using largest component with {len(G.nodes)} nodes")
Troubleshooting: See troubleshooting.md → Routing Issues
Creating Tutorials with OSMnx
When creating a tutorial that uses OSMnx:
Choose recognizable location
-
Use well-known places (e.g., university campus, downtown area)
-
Easier for readers to relate to
Cache the graph
-
Include downloaded graph in tutorial repository
-
Avoids download delays for users
Use small areas
-
Keep examples fast (<30 seconds to run)
-
Small bounding boxes or specific places
Provide visualization
-
Plot the network with routes overlaid
-
Makes results more tangible
Handle edge cases
-
Show what to do if node unreachable
-
Demonstrate connectivity checks
Common Patterns
Pattern 1: Campus Routing
1. Load campus
G = ox.graph_from_place("University Name, City, State, USA")
2. Find buildings as customer locations
pois = ox.geometries_from_place(place_name, tags={'building': True})
3. Create distance matrix
4. Build PDPTW instance
5. Solve and visualize on map
Pattern 2: City-Wide Delivery
1. Load city with bounding box
G = ox.graph_from_bbox(north, south, east, west)
2. Use address geocoding for customer locations
3. Compute network distances
4. Create VRP instance
5. Solve at scale
Pattern 3: Benchmark Comparison
Create two instances:
- Euclidean distance (traditional)
- Network distance (OSMnx)
Compare solution quality and computation time
Integration with Other Skills
Works with:
-
maintain-data-structures: Reference OSMnx data structures (Graph, GeoDataFrame, distance matrices)
-
migrate-module: When migrating real_map.py from old codebase
-
tutorial-creator: When creating real-world VRP tutorials (when that skill exists)
Example:
You: "Create a real-world PDPTW instance for Purdue campus" → osmnx-integration skill triggers → References maintain-data-structures for OSMnx Graph structure → Creates instance following workflow
Reference Materials
-
Examples: osmnx_examples.md - 10 complete examples
-
Troubleshooting: troubleshooting.md - Common issues and solutions
-
Data Structures: See maintain-data-structures skill for OSMnx structure details
Key Reminders
-
⚠️ Coordinate order: nearest_nodes(G, lon, lat) not (lat, lon) !
-
💾 Cache graphs: Save downloaded graphs to avoid re-downloading
-
🔗 Check connectivity: Ensure all nodes can reach each other
-
📏 Distance units: OSMnx uses meters, convert as needed
-
🗺️ Simplify graphs: Use simplify=True for faster processing unless you need exact geometry