Arcview Network Analyst

The basic network model is made up of links (arc segments) that have an associated attribute known as the impedance. The impedance represents the cost of travelling over the link or the measure of resistance to movement of goods through the link. Network centers or facilities represent locations, which either distribute resources, such as a pizza bakery, or attract resources, such as a store or school. Any place on the network in which resources get picked up or dropped off is referred to as a stop. However, facilities are associated with events, not stops

Networks typically have rules about how objects move through them. For example, left turns may be prohibited at certain intersections and bridges may be closed for repairs. Networks are often a combination of one-way and two-way streets, with multiple lanes going in different directions, and some roads will have speed limits imposed. Arcview Network Analyst allows you to model this as close to reality as possible.

The following rules* can be modeled in Arcview Network Analyst:

Travel cost:
The average cost of traversing a link, modeled as distance, time or any other cost unit.

One-way streets:
Streets that can be traveled in one direction only.

Turns:
Turns that are not allowed, i.e. left, right, straight or U-turn at an intersection, or turns that are more “expensive” in terms of travel cost, i.e. left turns at intersections.

Over- and underpasses:
A street that passes over or under another street, such that you cannot make a turn onto the road you are passing over or passing under.

Closed streets:
Streets currently closed to traffic or certain types of streets to avoid.

*You can actually model a lot more, but that requires the use of Avenue scripts. This page focuses on the basic Arcview Network Analyst functions only.