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October - December 2005
Sacramento County is facing challenges typical for a major metropolis with a growing population. Nestled between the San Francisco Bay area and Lake Tahoe in California, Sacramento County has a population of more than 1.2 million and encompasses 7 incorporated cities and 3,200 square miles of maintained roadway.
A current and accurate street network is vital for emergency dispatching, transportation routing, address matching, and other GIS-based operations that local government agencies use when providing services. However, fostering multiagency collaboration and developing maintenance procedures for common data can be a daunting task.
In 1995, county GIS staff partnered with the city of Sacramento to share common data and eliminate redundant tasks. Since 1995, the Sacramento Area Council of Governments (SACOG), the Regional Fire/EMS Communications Center, and area municipalities and local private utilities joined the county and city to form the Sacramento County Regional GIS Cooperative. In 2000, member entities accepted a common GIS base that would help the cooperative develop shared data layers.
The regional street network is the foundation of the cooperative's basemap. While responsibility for spatial maintenance of data layers resides with Sacramento County, municipalities retain ownership of all tabular attribute data and are held accountable for individual address range validation. However, coordinating ongoing spatial edits using legacy error reporting, interoffice correspondence on hard copy, and e-mail requests and reconciling sometimes contradictory tabular edits were laborious processes that needed improvement.
"Dispersal of workload and responsibility, in general, is an efficient and effective means for reducing staffing hours without sacrificing data quality," said Linda Luers, Sacramento Regional Fire/EMS Communications Center. "However, in our situation, the compilation and reconciliation of substantial data edits by member agencies had compromised our ability to effectively manage this critical data in the most efficient manner possible."
After receiving a state grant to develop a new homeland security data portal, the cooperative began the first of a three-phase plan for coordinating information management and distribution for all local government entities. The cooperative worked with GeoPrise.Net, a GIS consulting firm and Esri business partner, in developing a Web-based viewer and editing tool for collecting and managing the address range information used by the member entities' public dispatch systems.
The result was the Regional GIS Street Network Portal and Range Edit Web Utility. Built on existing GeoPrise.Net functionality and architecture, the portal enhances the standard GIS Web viewer to meet the cooperative's specific needs. With the new Range Edit Web Utility, users can view and edit street name components and address ranges, scrutinize pending edits proposed by additional off-site editors, and instantaneously validate network range connectivity. Supplementary administration utilities speed processes that were previously labor intensive by allowing administrators to accept or reject proposed edits within their individual jurisdictions and reconcile multiple edits suggested for the same record. Spatial and tabular data extracts based on multilevel filters as well as powerful reporting capabilities for current, edited, and archived changes further augment the application.
Built upon Esri's ArcIMS technology and Microsoft .NET, the Regional GIS Street Network Portal provides instantaneous access at any desktop with an Internet browser and sufficient user permissions via a dedicated virtual private network (VPN) connection. The user-friendly tools and interfaces help users, whether experienced or inexperienced, quickly become efficient and productive data editors.
According to Joe Concannon, senior GIS analyst for SACOG, "The elimination of complex and precarious workflows, as well as the resolution of communication and timing issues, has freed analysts from the burden of monotonous data maintenance tasks, once employing a great deal of time and effort."
Staff members who once spent hours on data quality control and multiagency coordination, can now perform real-time data editing and determine the accuracy of addresses. These tasks are essential in maintaining critical information for E-911 dispatching and emergency operations. In addition, staff can now devote more time doing what they do best-developing and growing GIS for the future. For more information, contact
Mark Perry, President
About the Author
Mark Perry is the founder and president of GeoPrise and has been involved in Web development and GIS for 10 years. He holds a bachelor's degree in civil engineering and a master's degree in business administration and management information science and is a licensed civil engineer.