What is GIS?
It is often difficult to define what GIS is since it has such a wide range of capabilities and can be used in any area of study dealing with spatial distribution and location. Physically a GIS is a collection of hardware, software, geographic and alphanumeric data, and personnel. It is used to prepare, present and interpret facts that pertain to spatial distribution. Technically a GIS combines database procedures, such as query and statistical analysis, with geographic capabilities dealing with geographic analysis and mapping. Its data components include spatial features stored in a coordinate system, and descriptive attributes stored in tabular form. The spatial features are arranged in spatial data layers, and the descriptive attributes are associated with the spatial layers. A GIS has the ability to integrate and analyze a large number of these spatial data layers at one time for a single location making it possible to perform complex analysis and modeling. This means that GIS is not just a map-making software, but an important spatial analysis tool used in research and decision-making.
In the field of transportation GIS has many applications. GIS is used to integrate mapping analysis into decision support for such transportation needs as facility management, site selection, network planning and analysis, vehicle tracking and routing, inventory tracking, and route planning and analysis. This support can come in the form of spatial database development, mapping, applications performing mapping automation, data integration, 3-D and other spatial analysis, user-interactive querying, and web-based and real-time applications. In the Volpe GIS Projects web pages a variety of examples of transportation projects are described such as data collection and risk analysis of the grade crossings for the FRA, and mapping of ambient sound levels for the FAA.
