Document Type

Working Paper

Publication Date



ransportation engineering, Geographic information systems, Transportation -- United States -- Planning, Intelligent transportation systems


Geographic information systems (GIS) are being increasingly deployed by transportation agencies to help them display, review, and utilize data. The primary items of interest are transportation facilities and services, which may take the form of highways, airports, bus routes, and seaports, among others. Using GIS software, transportation facilities are represented as geometric shapes; i.e., points, lines, and areas. However, it is increasingly apparent to GIS users in the field of transportation that a geometry-based approach is not sufficient.

The offered solution is to develop a feature-based GIS approach for transportation. The central requirement of such an approach is to have an unambiguously identified set of transportation features and a means of locating related features and attributes on or adjacent to the transportation features. For linear transportation features, the common location referencing system (LRS) is also linear. Usually based on milepoint offsets from a beginning point, linear LRSs are widely used by transportation agencies to locate data stored in numerous legacy databases. Some agencies may have multiple linear LRSs for various applications or topical areas. Data users unfamiliar with linear LRSs have difficulty using highway data provided by transportation agencies, and the correlation of linear and non-linear LRSs is generally quite difficult.

The result is that sharing of digital road map databases within and among organizations is difficult since there are no consistent ways of representing transportation features, and different decision rules exist as to what features to include and how they are identified. Numerous efforts are underway to develop a national standard for linear LRS design and implementation, including a set of field procedures to ensure that needed accuracy is achieved.

This paper will describe a means to unambiguously define transportation features using a simple set of naming rules. These rules will support linear and other forms of LRS for all types of transportation features, including airports, seaports, railroads, highways, transit services, bridges, intersections, signs, and related facilities and services. Such features may be displayed at multiple scales as point, line, and area graphical objects.


Catalog Number DP97-8.

Prepared for Presentation at the 1998 Transportation Research Board Annual Meeting.

A product of the Center for Urban Studies, College of Urban and Public Affairs, Portland State University.

Persistent Identifier