Mapping the Territory
Map 60,000 points in two years? No way. That was my initial reaction as coordinator of development for the new Geographic Information System (GIS) for Northeastern Rural Electric Membership Corporation (Northeastern REMC), a project that included the formidable task of mapping the utility’s entire 600 square mile service territory.
As it turned out, I was wrong. With the help of sophisticated and easy-to-use Global Positioning System (GPS) equipment and a great crew of technicians, we were able to complete the project in less than a year.
Creating a Multipurpose GISNortheastern REMC is a consumer-owned electric cooperative in Columbia City, Ind., supplying electric power to nearly 20,000 households in the northeastern part of the state. Our service territory includes two of the highest growth areas in nearby Ft. Wayne. We needed a comprehensive GIS to maintain our facilities and provide dependable service to our customers. Especially for utilities, an accurate GIS is critical. In a power outage, for example, field people without accurate maps may not be able to find faulty equipment quickly. That negatively impacts customer service and prolongs outage times.
Northeastern REMC’s old pre-GPS mapping system consisted of 150 separate drawings. The maps, with no data attached, were inaccurate and outdated. Worse still, only 25 percent of the service territory was actually mapped, and even that was without any specific map grid. Recent development was a major reason the maps had become outdated. Adding more customers meant more service facilities and equipment, and the old mapping system became more obsolete with each addition. As we tried to update our drawings, we couldn’t fit the new subdivisions into the old maps. That’s when we started looking to GPS for help with completing the GIS project.
The location of every piece of equipment Northeastern REMC owns had to be entered into the new GIS mapping system. It took 60 years to install all this equipment. In the end, we were able to find and map all of it in less than a year. But we couldn’t have done it without GPS.
Originally, we planned to use GPS as an engineering tool to accurately locate all the poles and transformers for engineering analysis. The GIS told us exactly how far each piece of equipment was from the next. We needed to know exactly where our wire was, how much there was and its size. In the past, we’d made rough measurements by pacing or using a measuring wheel, but we felt only GPS could provide the level of accuracy we needed for our engineering model.
Once we started looking into GPS, we began to think about other applications for the technology. For example, we could have the mapping system accessible in the trucks for line crews to use in the field. Then we thought staking engineers would probably like to have this information in their hands as well and customer service staff could use it in the office. Essentially, we started to understand that the GIS would be an auxiliary to our database that the entire company could use.
In the long run, we expect the new mapping system to make us more competitive. Every employee will have access to an accurate, comprehensive database and corresponding maps that will improve productivity and enhance customer service. We also expect efficiency gains in the office and in the field.
Versatile GPS Data CollectionThe first step in developing the GIS was to collect the data. For the GPS data collection, we chose the Thales Navigation Reliance Decimeter System (Thales/Ashtech, Santa Clara, Calif.). Reliance is a field asset management tool that was flexible enough to get the job done and accurate enough to provide dependable data. We had 60,000 points to collect, so Northeastern REMC’s GPS technician and Pathfinders, our GPS service contractor based in Ft. Wayne, were out every day with roving Thales Navigation devices, collecting as many points as possible. The versatility of the equipment allowed us to set up for what we needed on a daily basis.
Our Reliance GPS receiver was mounted in a vehicle or on a bicycle, or carried in a backpack on foot.
We designed a special bike mount, a re-engineered marine bracket originally used for mounting depth finders on fishing boats. The Reliance was mounted to a mountain bike for rural areas where the points were farther apart but couldn’t be readily collected with a vehicle. GPS field technicians were provided with the power and flexibility to easily reach most offroad points. We were able to collect 120 points each day with the bike.
GPS technicians also used a specially equipped minivan. Where points were closer together in developed areas, a technician could detach the receiver and place it in a backpack for walking. It typically took between five and 10 minutes to transition from one mobile setup to another.
By walking or bike riding, the technicians also had minimal impact on our customers’ property, and they were able to eliminate the traffic disruptions normally caused by standing vehicles.
Whether driving, riding or walking for data collection, the GPS technician occupied the point as closely as possible, and if necessary, shot an offset with a laser range finder by Laser Technology Inc. (Englewood, Colo.) and an electronic digital compass. He then entered those measurements and the attribute data into the Reliance system while collecting the point with the GPS receiver. At the end of the day, the data was downloaded into the home base GIS.
The GPS technicians also had access to our electronic survey tool station for hard-to-reach areas that made GPS readings difficult. In the few cases where our GPS technician was unable to acquire an accurate reading with Reliance—areas with heavy tree canopy, for example—we would simply send our subcontractor, Pathfinders, in with the powerful Thales Navigation GG Surveyor system to collect that point.
Using the GG Surveyor, which covers more satellites and therefore offers a better shot at a solution, Pathfinders was able to gather points easily, even in the most obstructed areas. I was very impressed when I saw the contractors walk into the woods for a minute and a half and come back with one- to two-foot accuracy in the trees.
The success we have had with data collection went beyond our expectations. We didn’t expect the GPS points to keep coming in as quickly and as abundantly as they did. There were few points that we had to revisit for reshoots. That level of performance makes the value of the GPS tool even greater.
We brought points into the map on a daily basis. We used the AutoCAD Map Software, enhanced with Autodesk GenMap software (Autodesk, San Rafael, Calif.). GenMap provided an interface between AutoCAD Map and our company database.
From the Reliance GPS, we downloaded an ASCII text file into AutoCAD Map, a task supported by GenMap’s import function. The system then combined coordinate and attribute information into an AutoCAD block. Each point on the map is designated by a symbol, which can be clicked to access point attributes. For example, each customer on the map will be represented by a meter symbol, with attached attribute data such as name and address, and even more detailed information such as the transformer serving that customer.
Maintaining Data AccuracyHigh accuracy was one of the main reasons we selected the Thales system. We found that when we stood at a point with it for about a minute and a half, we could easily achieve accuracy within two feet. We learned that if we went back and repeatedly measured the same point, our scatter pattern would only be 3' out in the open. Under heavy tree canopy we had to occupy the site for a slightly longer period of time, as with any GPS equipment.
As GPS users know, a key to obtaining accurate measurements is to have good satellite coverage. With access to more satellites, the GPS receiver can collect more accurate data faster. That means occupying the points and collecting GPS data when the most satellites are overhead. That can occur at different times of the day, depending on the satellite schedule. For detailed advance planning, we used the Thales Navigation Mission Planning module, a feature of the Reliance processor, which enabled us to plan each day for the best coverage.
Convenience and Support of GPS DeviceEase of use was a deciding factor for us in choosing the Thales GPS equipment. We were able to train our people in its use in less than two days. The menu-driven GUI was easy to understand, which allowed us to get up to speed quickly on the project. With this tool, the GPS technician did not need much support while in the field, even at the project start.
GPS technology is essential in a field asset management capacity. A huge portion of our service area had never been mapped and without GPS it never would have been mapped. Although we continue to refine and update our maps, the successful results we’ve already achieved with GPS have been impressive. We’re also confident in the accuracy of our work, translated into the accuracy of the final product—the Northeastern REMC GIS.