Mapping, Modeling, Simulation
Transportation is all about geography. It is moving people and goods from one place to another. According to the United States Department of Transportation Bureau of Transportation Statistics, transportation goods and services were responsible for more than 10 percent of the gross domestic product in the United States in 2002. Transportation drives employment, whether it be manufacturing, driving vehicles, or maintaining the infrastructure on which these vehicles operate. One of seven jobs in the United States is transportation related.
Transportation geography is concerned with the patterns of movement of people and goods. These patterns, also called networks, influence the cost and availability of goods and the delivery of services. At any given geographic scalelocal, regional, national, or internationalthe function of transportation networks has pervasive effects, both direct and indirect, on the economy, social structure, and environment for that area.
Because transportation networks are complex, developing networks that are safe, cost effective, and reliable typically requires considering a wide range of data that describes factors such as land use, economic conditions, and environmental considerations. In developed countries, transportation planning must take into account existing infrastructure and, for optimal efficiency, consider more than one mode of transportation. Instead of only one form of transportation, these networks employ a mix of types from automobile or railroad to pedestrian, bicycle, or light rail. This means that transportation planning can't be effectively handled in isolation from other factors.
GIS is an effective method for applying geography to problem solving. Datasets, data models, process and workflow models, maps and globes, and metadata are the building blocks for describing the earth; its contents and processes; and, more specifically, transportation networks. Using a geographic framework, GIS can integrate data incorporating diverse factors, resulting in solutions that realize cost savings through greater efficiency, better decision making, improved communication, and better geographic record keeping.
The ability to model many scenarios quickly means GIS can be used for evaluating the impact of new highway construction, identifying congestion points on a transportation network, analyzing traffic accidents and factors that contribute to their occurrence, or routing hazardous materials. The classic GIS transportation application is preparing a transportation plan. Not only does GIS enable participation in the planning process by a much broader group of stakeholders, but it can also be used in modeling both the current situation and future demand.
GIS tools and data sources have continually improved. Esri has advanced GIS beyond project-focused desktop applications to a complete system for authoring, serving, and using geographic information that encompasses desktop-, server-, Web-, and mobile-based GIS. The development of three-dimensional modeling provides a more comprehensive way for dealing with transportation planning than was possible with CAD or two-dimensional mapping. Software such as the ArcGIS Network Analyst extension has been designed specifically for analyzing transportation networks.
The ArcGIS Data Interoperability extension has greatly enhanced direct read and translation capabilities. Now data created in many more formats can be immediately used by a GIS. Imagery data is now more available than ever. The quantity, quality, coverage, currency, and costs associated with remotely sensed data have all improved significantly in the last several years. Integrating imagery with other data sources helps maintain data that is more accurate and current.
Through mapping, modeling, and simulation, GIS applications for transportation can enhance the decision-making process by communicating more effectively with policy makers and enabling collaboration with many stakeholders who may or may not be specialists.
Articles in the Focus section of this issue illustrate how GIS is being applied to various aspects of transportation. The County of San Bernardino, California, is automating its road book so that it can not only produce more current and complete maps of its extensive road system but also document the status of the system to meet state requirements.
A study by landscape architecture students is promoting a healthy, alternative transportation mode for area childrenwalking. With GIS, these students could evaluate the safety of various routes, model various solutions for eliminating the hazards they identified, and weigh the cost of required changes to determine the most cost-effective solution.
Transportation is a significant cost when evaluating the economic viability of biofuels as an alternative energy source. Researchers at the University of Florida most comprehensively addressed these transportation costs using the ArcGIS Network Analyst extension to calculate haul times for biomass materials that are the basis for determining the availability and real costs of fuel from various sources.