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This research produced a data model that can be adopted by transportation agencies,

by transportation geodata standards groups, and by Geographic Information System in

Transportation (GIS-T) software vendors. The research (a) established consensusbased

functional requirements for a transportation multimodal, multidimensional location

referencing system (MDLRS) data model; (b) developed an MDLRS data model

that meets these functional requirements; and (c) developed guidelines for implementing

the MDLRS data model in transportation organizations.

Through a workshop of stakeholders, this research identified ten core functional

requirements that form the essence of the MDLRS data model: spatiotemporal referencing

methods, temporal referencing system/temporal datum, transformation of data

sets, multiple cartographic/spatial topological representations, resolution, dynamics,

historical databases, accuracy and error propagation, object-level metadata, and temporal

topology/latency. A number of existing data models and standards were considered

in the formulation of the MDLRS data model. None of these existing models and

standards supported all of the functional requirements. However, as a group, they provided

many of the building blocks for the MDLRS model.

Conceptual and logical schematics of the MDLRS were established. The conceptual

model illustrates the semantics of the model as they relate to the central concepts of the

transportation feature and event being referenced to systems that are based on linear

and nonlinear data. To support interoperability, the logical model is expressed in unified

modeling language (UML) notation. The UML local data model is in a normalized

form in which object classes can be created directly from the model.

The MDLRS model uses Coordinated Universal Time (UTC) and the Gregorian calendar

as the temporal datum and operates on the assumption that there is one temporal

reality of a phenomenon along a timeline. Temporal relationships are used to derive

temporal topology. The MDLRS model distinguishes between the spatial and temporal

elements of objects. It uses scale applicability as the central notion for maintaining

consistency of multiple geometric and topological representations.

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