Linking Spatial and Transportation Data

Abstract

Transportation is inherently a geo-spatial activity, involving the movement of people and/or things from one geographical location to another. Not surprisingly, therefore, much of the data needed to support transportation analysis, planning, and operations are associated with spatial location. Spatial data used in transportation include: characteristics of the origins and destination locations for trips; descriptions and measures of connectivity and impedance for alternative paths between origins and destinations; locations and descriptions of features and points of interest along a transportation network, and the dynamic location of transport vehicles moving between origins and destinations. Given the strong linkage between transportation and geo-spatial data, it seems that the transportation community would be an early adopter of geographic information systems (GIS) and other geo-spatial technology. This has not been the case. Transportation planners, in particular, have been relatively slow to embrace GISs as an integral component of their analysis toolkit. Even today, a GIS often used merely as a medium for presenting transportation data or the results of transportation analyses on a map, while its real strengths for data integration and geo-spatial analyses go underutilized. The reasons for this are partly historical and partly due to differences in how geo-spatial data are treated in GIS software versus transportation network models. This chapter explores both the historical context and differences between geospatial features used in GISs and network models. It concludes with a description of specialized transportation data structures that might be incorporated into GISs to fully address transportation application needs.