ArcGIS Tutorial: Types of network analysis Layers (iii)

　　Vehicle routing problem (VRP)

In general, fleet dispatchers are required to make decisions about vehicle distribution. Such decisions include how to optimally assign a group of customers to a fleet, and arrange their access order and schedule. The goal of solving this problem is to provide customers with a high level of service by complying with all time constraints and minimizing the overall operating and investment costs of each route. When these constraints are met, the route is completed based on existing resources and meets the time limit imposed by the driver on shifts, travel speeds and customer commitments.

Network Analyst provides a vehicle distribution solver to determine solutions for such complex fleet management tasks.

To transport the goods from the central warehouse location to the grocery store as an example. There are three trucks available at the warehouse location. The warehouse is open from 8:00 to 5:00 and all trucks must return to the warehouse within this period. Each truck has a capacity of 15,000 pounds, which limits the amount of cargo it can deliver. Each store has a specific quantity requirement (lbs) for the goods that need to be transported, and each store has specific requirements for the delivery time limit. In addition, the driver can only work eight hours a day, ask for lunch time, and based on the driving workload and to provide services to the store to pay the workload. The goal is to derive the driving line (or route) for each driver so that delivery can meet all service requirements while minimizing the total time spent on a particular route. Shows the three routes obtained to solve the problem of vehicle distribution.

　　

　　Location Assignment

Location allocation helps you select facilities from a set of facilities that require action based on potential interaction information with demand points. For example, it can help you answer the following questions:

• For an existing set of fire stations, where can the new fire station provide the best response time for the community?
• If a retail company must reduce the number of stores, which store should it close to continue to meet the most comprehensive needs?
• Where should a factory be built to keep the shortest distance from the distribution center?

In these examples, facilities are fire stations, retail stores, and factories, while demand points are buildings, customers, and distribution centers.

The goal may be to minimize the overall distance between demand points and facilities, maximize the number of demand points that can be overwritten within a certain distance of the facility, reduce the allocation demand with increased distance from the facility, or maximize the demand in a friendly competitive facility environment.

The results of the location allocation analysis are shown to determine which fire stations are redundant. Provides the following information for the Solver: a set of fire stations (facilities), the midpoint of the street (demand points), and the maximum allowable response time. Response time is the time a fireman takes to arrive at a specified location. The location-allocation solver shows that the fire department can shut down some fire stations while still maintaining a three-minute response time.

　　

　　Time-related analysis

All of the solvers listed above can be used to merge real-time traffic data and historical traffic data into network analysis so that you can find the best route for a specific time of day, and find the best location to pre-locate an ambulance at 8:00, 12:00 noon, 4:00, etc. and generate a service area at different times of the day. The results of any analysis may vary at different dates and times due to changes in traffic flow conditions and travel time.

ArcGIS Tutorial: Types of network analysis Layers (iii)