Five transit systems' experiences with geographic data systems technology investment.
California, United States
Fairfax City, Virginia, United States
Newark, New Jersey, United States
Portland, Oregon, United States
Seattle, Washington, United States
Best Practices for Using Geographic Data in Transit: A Location Referencing Guidebook: Defining Geographic Locations of Bus Stops, Routes, and other Map Data for ITS, GIS, and Operational Efficiencies
Summary Information
Effective life-cycle management enables the unambiguous sharing of information between applications. The best practices related to ITS and sharing among applications assumes that a robust data management approach is in place. Key best practices and lessons learned are included below that further facilitate effective spatial data sharing among applications.
- Define standard access methods to share transit feature data and other spatial data. Centralize the methods as stored procedures or middleware:
- A typical computing architecture supported by many transit agencies is the Client-Server model, with a centralized database management system.
- An alternative approach to the centralized client/server approach is to standardize and centralize the interface definitions between the core database and clients that need information.
- Manage application integration using an enterprise-wide repository of integration metadata. Develop the repository incrementally as each project is developed:
- Integration metadata do not document the data model used within applications systems, rather they describe the responsibilities and conditions that apply to the use of the interface.
- Integration metadata contain information about the communication content, the identities of sender and receiver, and the interaction process mechanics and business implications.
- A simple and crude repository is useful if it helps developers examine the impact of changes or to reuse metadata into applications.
- Adopt a data maintenance policy that ensures that applications start with the same data sets. Synchronize data, update schedules, and standardize procedures.
- Utilize a common base map throughout the agency to increase consistency, decrease redundancy, and reduce costs.
- Define a single source for base map conversion and distribution within an agency.
- Have a clearly documented and understood methodology for updating all base maps within the agency to minimize and manage inconsistencies.
- Maintain a central core set of data that can be distributed and utilized by all systems and users through the agency.
- Use GIS and an enterprise-wide database management system to centralize corporate spatial data.
- The data-centric approach must replace the application-centric approach to overcome "stove-pipe" implementation of applications.
- Standardize on a single base map; store and manage the base map centrally.
- Define a corporate transit feature dictionary and define an enterprise data model; store and manage the transit features centrally.
- Establish a data quality process and enforce internal data standards/policies.
- Assign responsibility for data set development and maintenance.
- Develop key look-up tables for location referencing methods (including a street name alias table).
Successfully and efficiently sharing information requires a deliberate degree of standardization across the enterprise. Users must share a common vocabulary including data meaning and format. To benefit fully, the data must be stored and accessed similarly. Centralizing the data and access methods will ensure that if there are changes made, then their impacts will be more easily managed. This experience and guidance addresses the ITS goal of efficiency.