A few years ago, the Hillsborough County Property Appraiser's Office in Florida had a difficult time keeping up with appraisal work because the required imagery was not available. Traditionally, the County purchased hard-copy aerial photography every three years. That frequency, however, did not keep pace with local development and growth. Hillsborough County includes the municipalities of Tampa, Plant City, and Temple Terrace and adds 18,000 new parcels annually. Also of concern, past aerial projects provided imagery to only a few participating large agencies. County offices, the public, and Businesses were charged for copies to offset the cost. The traditional approach, in effect, prevented potential imagery-using organizations from accessing a key resource. Nancy Halvorsen, GIS manager, and other existing and would-be imagery users set out to get the imagery their GIS work demanded.

The Property Appraiser's Office formed and pledged to coordinate the Hillsborough County Public/Private Aerial Initiative (HCPPAI). Part of the driving force behind the initiative was the fact that the Property Appraiser's Office valuation teams, the GIS department, and the public used a variety of Esri software along with aerial photography to examine the extent of property ownership. Numerous government agencies rounded out the group. By the spring of 2000, the group began to meet regularly.

HCPPAI members shared their administrative and technical knowledge, including how the imagery would work with the seats ofArcInfo, ArcView, MapObjects, and ArcIMS in use. They drafted a memorandum of agreement to guide the project. The document detailed such things as the contribution expected of each participant and the guidelines for deliverables.

By summer 2000, HCPPAI began the search for an imagery vendor to take on some nontraditional requirements. Several aerial photography firms were interviewed. The group set strict cost schedules and delivery dates. The toughest requirement involved licensing. HCPPAI insisted on the right to distribute and use the data without restrictions. EMERGE of Andover, Massachusetts, an Esri Business Partner, includes that type of license in its typical contract. Unrestrictive licensing, history of on-time delivery, and overall data quality all contributed to HCPPAI selecting EMERGE to collect and deliver three-foot resolution color imagery covering 1,243 square miles including the County and some extended coastal coverage.

Because of this vendor's completely digital process, by January 2001, just weeks after the initial data capture, the Property Appraiser's Office began to receive data. As members picked up data, a subtle benefit of the initiative began to surface: each member now had the exact same base layer, which simplified sharing other data layers.

The Property Appraiser's Office didn't waste a moment in taking full advantage of the up-to-date coverage. EMERGE imagery now serves as the backdrop for the Property Appraiser's Office ArcInfo sessions that focus on ArcEdit. These sessions are part of the Intranet served by , which serves 10,000 County employees and is a very popular part of the Property Appraiser's Office public Internet site. The Property Appraiser's Office currently uses ArcIMS to link the imagery to its mass appraisal software. The Hillsborough City/County Planning Agency uses the imagery to develop future land use plans and for an environmental Web site powered by ArcIMS. The Sheriff's Department of Hillsborough County carries the imagery on laptops in the field, using it to locate access roads and structures. Tampa Electric uses the imagery to locate and manage its light poles.

HCPPAI is working toward a regional initiative and hopes to expand this first agreement to explore the purchase of other items such as software, hardware, and other data.

For more information about Hillsborough County Property Appraiser's Office, contact Nancy Halvorsen (tel.: 813-276-8873, e-mail: halvorsn@hcpafl.org). For a list of the many government agencies that make up the HCPPAI, or for more information about EMERGE, contact Drew Fisher, director, Business Development, EMERGE (tel.: 813-631-1588, e-mail: apfisher@emergeweb.com).