GIS: Tallahassee Electric's GIS: Design with Future Use in Mind
The City of Tallahassee Electric Utility overhauls its antiquated record-keeping system and develops a GIS.
By Jane Cooper

Sometimes a major disaster clears the way for revolutionary change. That seems to explain why the small city of Tallahassee, Fla. (population: 135,000) has been able to implement a world-class geographic information system (GIS), one that combines efficient data collection and maintenance with a versatile data structure.
      Wayne Horner, Tallahassee's utility GIS project manager, explains how it started: "Hurricane Kate rolled through here in 1985 and wiped out major parts of the city. When it came time to claim for disaster relief, our infrastructure records were so inadequate that they did not provide an accurate picture of what we had lost. In the Electric Department, for example, we found that our initial estimates covered less than one third of our actual losses."
      Beyond replacing lost equipment, the City of Tallahassee Electric (COTE) utility also recognized the need to overhaul an antiquated paper record-keeping system, and develop a relational database that could, for example, display the names and addresses of all customers served by a particular transformer. Horner, along with other staff and consultants, spent several years investigating GIS technology, evaluating proposals, and designing their system requirements. Now COTE is well into the process of collecting field data about its electrical network, which serves 90,000 customers over an area of 270 square miles.
      The Mobile Data Collection System maps the location of poles, lines, and other electrical equipment using differential geographic positioning system (GPS) and laser rangefinder equipment. Field staff strap on an orange backpack that carries about 15 pounds of GPS communications and signal processing equipment. Signals from satellites and a GPS base station identify the operator's position to an accuracy of about one foot. This position data is fed to the screen of a portable computer that displays the operator's location as a mobile "you are here" dot.
      Equipment can be mapped by simply walking over to it and using the pen-based PC to enter the point in the database. Additional points can be added to the database with a hand-held laser rangefinder, which is used when tree cover inhibits use of the GPS. "This has worked quite well," adds Horner, "We have used two different models of rangefinder, and each one is prone to compass errors. These don't affect you if you're targeting objects within 100 yards or so, but for longer distance work we have to check the compass calibration every day."
      For location purposes, background maps of Leon County are stored as separate data layers and can be displayed on the data collection screen as reference maps. The accuracy of these maps varies, but it does not affect the accuracy of the GIS. The points and other features of the GIS are not actually connected to the background maps. When more accurate maps become available, the existing map layer can be replaced. In fact, better maps are on their way. New digital orthophoto images of the county were produced by aerial photography in the spring of 1996 through a local government contract. These photos are being converted to vector images of streets, buildings, streams, and other line data to supply COTE and other Tallahassee departments with improved background maps.
      The mobile interface to the GIS is an enhanced version of PenMetrics' FieldNotes application. With a stylus or "pen" the operator opens menus and selects attributes from a display of specific choices. In developing the system, COTE used contract programmers to develop an easy-to-use data collection program tailored to the city's requirements. An interface was written in C++ to map the PenMetrics flat data model to the relational model used by the host VISION*/ORACLE database from SHL VISION* Solutions. The VISION*Express rapid application development tool was used on the database side to create a set of rules that prevent the entry of invalid attributes or parameters. These customizations ensure that data can be collected quickly and in a thoroughly standard, quality-checked format. "We spent over six months developing this interface," observes Horner, "but it was worth it. It's an ideal tool for our use, and for other utility companies. We have realized some cost recovery for our efforts by selling the system to other organizations."
      Each day, data collection staff download a section of the GIS database, add to the data, then upload the revised version. Future plans call for real-time database updates by means of a radio link between collection staff and the central database. This will be essential after the initial data collection effort, when the system will be managing daily work orders and receiving simultaneous updates from many users. "We chose radio," explains Horner, "because the air waves are free once you have made the initial investment in equipment. We considered cellular digital technology, but the ongoing charges per minute or per packet of data are a definite drawback."
      Designing the database structures occupied Horner and his team for over a year. They knew their GIS had to evolve to a full spatial data management (SDM) system that could handle electrical connectivity data for network analysis, and could support COTE's Work Order Tracking System. Staff in the field repairing lines and providing electrical service would need to receive their work orders via computer and report their changes to the network on the same computer. If any significant time lag occurred in data entry, no one would be able to trust the system. An open, industry standard, relational database was clearly required to manage both spatial data and attribute data of COTE's network. This would ensure the widest possible scope for data analysis, maintenance, and reporting.
      As of March 1997, COTE has mapped just over 10 percent of its asset base and proven the usability of its methods. The utility's regular staff were able to handle the initial test phase, but not enough of them are available to map the rest of the network within an acceptable time period. A team of contractors will be hired to collect the remaining data over the next 12 to 18 months.
      The total cost of system development for COTE is about $200,000. Another $200,000 will be spent each year on salaries, licenses, hardware maintenance, and other system operating costs. In return, the utility expects to see major cost savings through having better information available for maintaining and engineering the electrical network.
      Fortunately, COTE's senior management did not insist on the SDM justifying itself through projected cost savings. It is not easy to create reliable projections in the early stages of a project. According to Horner, "Everyone here understood that we needed an SDM to remain competitive and to effectively manage our network. The advantages of going digital did not have to be justified."
      As the data collection project gains momentum, interest in the SDM system is growing among COTE managers. A number of applications are in the works to improve the handling of network planning and design, load flow analysis, trouble calls, tree trimming, and the joint use of poles with other utilities, to mention a few examples. Interest is also growing in other city departments, notably water and traffic management, where managers are starting to see beyond the mapping capabilities of SDM and glimpse the data analysis potential. For example, all city departments will be able to coordinate their construction plans for maximum efficiency.
      The city of Tallahassee has achieved its success as the result of much careful shopping in the GPS/SDM marketplace and attention to detail in system design. Other utilities and other cities should be able to learn something from this experience without waiting for a hurricane to strike.

About the author:
Jane Cooper is a market research assistant at SHL Vision*Solutions in Ottawa, Ontario, Canada. She may be reached at 613-236-9734 or via e-mail: [email protected]

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