Logistics Optimization Project

Author: Islam Md Jubayer

Description: This script optimizes delivery routes using OR-Tools and visualizes them using Folium.

try: import ortools from ortools.constraint_solver import routing_enums_pb2 from ortools.constraint_solver import pywrapcp except ModuleNotFoundError: raise ImportError("Error: OR-Tools library is not installed. Please install it manually using 'pip install ortools'.")

import folium import numpy as np from geopy.distance import great_circle

def create_distance_matrix(locations): size = len(locations) distance_matrix = np.zeros((size, size))

for i in range(size):
    for j in range(size):
        if i != j:
            distance_matrix[i][j] = great_circle(locations[i], locations[j]).km

return distance_matrix

def solve_vrp(locations): if not locations: raise ValueError("Error: Locations list is empty.")

distance_matrix = create_distance_matrix(locations)
num_locations = len(distance_matrix)
num_vehicles = 1
depot = 0

manager = pywrapcp.RoutingIndexManager(num_locations, num_vehicles, depot)
routing = pywrapcp.RoutingModel(manager)

def distance_callback(from_index, to_index):
    from_node = manager.IndexToNode(from_index)
    to_node = manager.IndexToNode(to_index)
    return int(distance_matrix[from_node][to_node] * 1000)

transit_callback_index = routing.RegisterTransitCallback(distance_callback)
routing.SetArcCostEvaluatorOfAllVehicles(transit_callback_index)

search_parameters = pywrapcp.DefaultRoutingSearchParameters()
search_parameters.first_solution_strategy = routing_enums_pb2.FirstSolutionStrategy.PATH_CHEAPEST_ARC

solution = routing.SolveWithParameters(search_parameters)

if solution:
    route = []
    index = routing.Start(0)
    while not routing.IsEnd(index):
        route.append(manager.IndexToNode(index))
        index = solution.Value(routing.NextVar(index))
    route.append(manager.IndexToNode(index))
    return route
else:
    raise RuntimeError("Error: No valid route found.")

def plot_route(locations, route): if not route: print("No valid route found.") return

map_center = locations[0]
map_route = folium.Map(location=map_center, zoom_start=12)

for i, loc in enumerate(locations):
    folium.Marker(loc, popup=f"Location {i}").add_to(map_route)

route_coords = [locations[i] for i in route]
folium.PolyLine(route_coords, color='blue', weight=2.5, opacity=1).add_to(map_route)
map_route.save("optimized_route.html")
print("Route saved as optimized_route.html")

if name == "main": delivery_locations = [(37.5665, 126.9780), (37.5759, 126.9768), (37.5800, 126.9700), (37.5622, 126.9832)]

try:
    optimal_route = solve_vrp(delivery_locations)
    print("Optimized Delivery Route:", optimal_route)
    plot_route(delivery_locations, optimal_route)
except (ValueError, RuntimeError) as e:
    print(str(e))