By Bill McGarigle

The layers of information in existence at the city and county level of government are agencies to relinquish control of data to GIS utilities.

Considering the decade-long tenure of GIS in the back room, the typecasting of this technology as a specialized engineering tool is understandable. It is also dated. Interoperability standards, integrated databases and recent advances in technology have changed that image. Today there is an increasing awareness that GIS is an enormously versatile tool with potential applications and benefits for

nearly every branch of local and state government, from policy making to surveying. This is especially true of GIS as an enterprise utility.

In an enterprise GIS with a standardized base map and synchronized address database, data layers from many departments can be called up to show geographic relationships and developing patterns, enabling policy

makers to have a far better understanding of how different issues interrelate and to "see" how decisions affecting one part of the equation can affect others. GIS software can be used to play out planning scenarios, virtually fly over, under or through areas in 3D and in color to see the short and long-term effects of decisions. A centralized system can promote data sharing among agencies and departments, eliminate duplication, lower operating costs and increase

efficiency. It can contribute to better policing and saving lives, and it can promote greater transparency in the decision-making processes of local government and serve as a catalyst for profitable partnerships with the public sector - the list is inexhaustible.

Maximizing GIS benefits across local government on this scale is possible only through an enterprise-wide system, a GIS utility, in which agencies and departments use a common base map, have a single, synchronized address database and share selected data across the enterprise. San Diego, Philadelphia and New York City have systems at varying stages of expansion or development. Each offers perspectives on the benefits of a GIS utility and what it takes to get one started in local government.

San Diego

Having worked with the technology since the 1980s, San Diego was one of the first city-county jurisdictions to develop an integrated GIS utility. Today they have a GIS utility that is regional in scope and an agency, SanGIS (the San Diego Geographic Information Source), which is responsible for data maintenance and warehousing, keeping the software and hardware current and available to all city and county departments.

The organization maintains a regional database with about 200 different layers of information and has a data-sharing agreement with the San Diego Area of Governments and land-base subscriptions with 16 private and public sector agencies. SanGIS is also the agent through which public and private sector entities purchase enterprise maps and data

developed by member agencies. The city developed its first shared base map by digitizing maps acquired through a partnership with San Diego Gas & Electric. SanGIS (formerly the Regional Urban Information System) increased the accuracy of the base map by geocoding and synchronizing

the address databases used by the various agencies. Orthophoto capability was added later. SanGIS now has an interactive map section on their Web site .

According to Dianah Neff, San Diego deputy city manager and chief information officer, enterprise GIS has been highly valuable in policy-making decisions. "We are using the GIS to assist in updating the citys general plan," said Neff. "For example, when the staff meets with neighborhood groups to discuss potential growth issues, we use various map layers to show how the existing capacity for water, sewer and roads lines up with projected new housing and urban-growth patterns. Also, when the city council is looking at planning and zoning issues, we are able to bring up all the map layers and data relevant to those areas and display them."