Home to scenic rivers, creeks, and bays, Hernando County, Florida, on the central west coast of Florida north of Tampa Bay, offers much more than sandy beaches. Rich in culture and history—it was named for Spanish explorer Hernando de Soto, who led an expedition through the county in 1539—the county owes much of its early settlement to railroads. In fact, today, these unused railways have been converted to greenways for those who wish to experience Hernando County at a slower pace.

Yet, like all counties, Hernando County has administrative issues. Foremost among these has been addressing. Addressing has plagued most government officials for decades. Although it is a fundamental element for any county, address information in many areas has not kept pace with technological advances.

In the summer of 2003, Hernando County began the process of updating its addressing system to a customized GIS-based application. The Property Appraiser (PA) existing work flow for assigning addresses was outdated, confusing, and in need of modernization.

"Addressing was the greatest common factor identified from our GIS stakeholder meetings," says Nick Nikkinen of the Hernando County Property Appraiser's Office. "Alvin R. Mazourek, the Hernando County property appraiser, met the challenge and took the lead in an effort to eliminate redundancy, increase accuracy, allow multiple departments electronic access to the database, and help reduce emergency response time through more accurate addresses."

Previously, a building's or structure's address was assigned when a subdivision was created, then keyed into a database at the Building Department. Copies of the plat, plan sheet, and original address application were then forwarded to the PA's office in hard-copy format. The PA then put the information into the addressing information database and distributed it to other county departments, which then entered the information into their respective databases.

The use of hard-copy maps was also a source of concern. If the maps were damaged by flood or fire, there was no other readily accessible source of original address information. Moreover, since addressing information was distributed in hard-copy format, rather than electronically, it was not easily shared with other agencies, which caused the PA's office and the Emergency Management, Engineering, and Building Departments to enter data in different databases. This multiple data entry was not only redundant, it was also inconsistent. Each database was independently edited, resulting in countywide inconsistencies.

All of this boils down to the fact that the main issue facing the PA was the lack of an addressing manager. The county turned to 3001, Inc., a Florida spatial data company and Esri Business Partner, to aid in updating its addressing system. The county chose 3001 for its reputation as well as its previous experience in developing a GIS-based addressing system. 3001 updated the county's addressing databases and created a custom extension to work within ArcGIS (ArcInfo, ArcEditor, and ArcView), making address assignment much easier and user friendly. This project consisted of two parts: (1) data creation and legacy data migration and (2) custom application development.

Data Creation and Legacy Data Migration

Thus, a two-year project was begun to improve the accuracy of the county's parcel basemap by reworking the coordinate geometry based on deed records. It was during this project that the PA realized the need for a more accurate method of storing addresses. The previous method did not account for parcels containing multiaddress structures, such as apartments, condos, and business centers. 3001 recognized the potential of the new and more accurate parcel basemap and utilized the ArcGIS mapping capabilities to derive polygon centroids from the parcels to create a point data layer.

The point data layer was then used as the structure layer for the addressing data model. Using a spatial intersect within the ArcMap application of ArcGIS Desktop, the parcel identifiers were conflated to the structure points. The accuracy of the structure layer was based on the accuracy of the parcel basemap, as well as the size of the parcel itself. In other words, the smaller the parcel, the greater the level of spatial accuracy. To complete the parcel identifiers, the parcel basemap was intersected with the structure points. Once the structure point layer was created, the legacy address information was extracted from a variety of sources. This address data used the parcel identifier to link the address data to the correct structure point in the structure layer.

Upon completion of this process, 3001 obtained a master index of street names from the Hernando County Post Office to validate and remedy name errors within the structure point data and street centerline data. The Attribute Transfer Mapping tool on the Spatial Adjustment toolbar was used to transfer correct street names from the parcel basemap to its corresponding street segment, where required. The data was standardized by utilizing street abbreviations downloaded from the United States Postal Service Web site.

With the standardization of the street names, 3001 utilized custom ArcObjects scripts for data processing. ArcObjects, the underlying framework of the ArcGIS suite, was utilized in nearly every aspect from custom data processing to developing the actual addressing application itself. The custom scripts used for this portion of the project assigned each structure point to its corresponding road segment.

When the county assignment was completed, street segments provided an accurate range using the existing addressing data and creating a rule stating line directionality goes from low to high according to the address data for each segment. Once all points were assigned to their corresponding road segments, 3001 created a simple query for each segment to derive high and low address numbers.

Application Development

The addressing extension was developed to work within ArcGIS Desktop software's ArcMap application to harness the capabilities of a robust GIS, as well as integrate 3001 user interfaces to allow for the ease of maintenance of the newly created data sets. The PA took great care in selecting a database platform for its GIS spatial and address data repository. ArcInfo licenses were acquired to allow for editing the ArcSDE databases, as well as some of the more advanced functionality that is available for this tier.

The PA chose a dual-node Linux Red Hat Advanced Server 2.1 operating system and an Oracle9i database management system utilizing Transparent Application Failover (TAF) capabilities. ArcSDE 8.3 was used with a direct connection for ArcSDE operations to allow the PA to utilize the TAF setup. Every component in the database server has at least one redundant counterpart, thus ensuring virtually no downtime even in the event of a server crash. The system automatically load balances connection requests between the two servers and is capable of hosting hundreds of simultaneous client connections.

"We're very satisfied with the addressing software," says Manuel Padron, the Hernando County addressing manager. "We can create or modify up to 350 addresses a day. The changes have increased the Addressing Department's efficiency and consistency. Between the program and department operating procedures, the Addressing Department can now view, modify, distribute, and analyze data. In addition, a very important benefit of the system is that it saves time in an emergency, when every second counts."

For more information, contact Nick Nikkinen, Hernando County, Florida (e-mail: NickN@co.hernando.fl.us, tel.: 352-754-4190), or Sarah Bailey, 3001, Inc. (e-mail: sbailey@3001data.com, tel.: 352-379-3001, fax: 352-377-4324, Web: www.3001data.com).