Source: BTS, Transportation Statistics Annual Report. Since the 1970s, trade with the United States has been an increasingly important driver of economic growth for Canada and Mexico. Moreover, freight transport between Canada and the United States has become the number one growth factor in the trucking industry, underlining the dependency
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B.3 – Gateways and Transport Corridors in North America
Authors: Dr. Jean-Paul Rodrigue The North American economy is articulated along major corridors that connect commercial gateways to their hinterlands. 1. The Spatial Structure of Corridors Transport corridors are considered the backbones of transportation networks, linking major gateways and hubs through a convergence of freight and passenger flows. Most often,
Network Data Models section migrated
Network Data Models
Continue readingObject-Oriented Network Model
A transport network can be represented by two object classes, defined as Link and Node, which are inherited. Because of the topological attributes of a network, a connection relationship has to be established between the link and node classes. It defines and nature and extent of the geometric connectivity supporting
The ESRI Shapefile Model
Introduced in the early 1990s, the shapefile format is one of the most common GIS vector data formats compatible with the majority of software platforms. It was designed as a compromise based on the most widely used database format of the time by indexing it with a feature file. It
Turn Penalties at an Intersection
The above table represents the turn penalties for a typical intersection between two streets represented as Node A. From each direction, there are three possibilities; going straight ahead, turning left, or turning right. This intersection consequently has 12 turns, each having a specific attributed penalty. Straight flows (1-3, 3-1, 2-4,
Creation of a Connectivity Matrix with a Link Table
A links table can easily be used to construct a connectivity matrix, a core element for measuring accessibility. It can be achieved by using a simple algorithm:
Topological Representation of a Simple Network in a Relational Database
A network can be represented using two tables, one defining nodes and the other defining links. The three core elements (fields) of a nodes table are unique identifiers and locational attributes in a coordinate system, such as latitude and longitude values. In the above example, coordinates are in decimal degrees,
Routing in a Network Data Model
Routing in a network data model can be simulated if the impedance is available to links and nodes. For links, impedance is often characterized by travel time, while turn penalties are often used to characterize impedance at nodes; how difficult (if possible) it is to turn in one direction, as
Geocoding in a Network Data Model
Geocoding is possible if a linear referencing system is embedded in a network data model. One of the most common linear referencing systems is the address system, where each link has a corresponding street name and address range. The above address range illustrates even (right side) and odd (left side)