In many rural areas of the county, emergency medical and fire responders are volunteers who are very familiar with the roads, residences and landmarks of their community. But as the population expands and new construction proliferates, a logical, consistent frame of reference becomes increasingly necessary for navigation. An address system generally consists of address numbers in sequence along a uniquely-named road with odd and even numbers on either side. Good addressing has become crucial not only for public safety personnel, but is also invaluable for out-of-town visitors, the package delivery person and utility workers, to name just a few.

Today, address systems can be captured in a GIS (geographic information system) as a computerized map. In a GIS map, every feature is linked to a record in a database, which makes it possible to query for locations, perform analysis based on spatial relationships, and even track events through time. Wireless enhanced 911 systems depend on a GIS basemap that includes roads, addressed structures, railroads, rivers, mile markers, and jurisdictional boundaries like city limits, emergency service zones, county boundaries, etc. Because GIS-trained personnel are required to build and maintain the county basemap, the assignment of new addresses was officially transferred from the Public Works Department to the GIS Department in 2005. (Addresses inside Billings and Laurel city limits are assigned by the respective Fire Departments.)

Sample Basemap

Building a basemap requires, first of all, collecting x,y coordinates for features like roads and buildings, a process known as "georeferencing" data. GPS data collection of existing roads and addressed structures was completed in 2003. New construction is being tracked and GPS'd on an ongoing basis. The GPS'd road lines and address points were then assembled in the GIS and the records in a database "standardized," meaning the information was formatted with uniform spellings, abbreviations and codes. This allows for more efficient address look-ups with better, consistent results. The database design must also be well coordinated with various agencies to ensure accessibility and security of the information.

In addition to standardization, every map feature in the database must undergo "data verification" to reconcile any discrepancies between the existing address records of various departments, including Public Works, the Department of Revenue, Elections, the Post Office, etc. The process is labor-intensive -- with over 61,000 address points and 12,000 road line segments - but in the end, a centralized master address record system can be shared by multiple departments, eliminating conflicting addresses records and the time and money required to maintain separate address databases in every department.