Mar 29 2007

Moving Maps From the Sky

Two governments -- a small county and a large city -- use GIS and GPS to deliver more services, more quickly.

In Florida, Santa Rosa County’s Aleta Floyd, left, and Val Jarvis say they intend to keep extending the services supported by the county GIS as agencies provide new types of data for inclusion in the system.

The list of services that taxpayers expect from local governments seems endless: emergency response from police, fire and medical teams, along with public works that run the gamut from water, sewerage and electricity to garbage collection and road maintenance.

At some point, providing any one service comes down to a single important question: Where? Where’s the house, where’s the pothole, where’s the fire hydrant, where’s the landfill, where’s the road, where’s the school? And, equally important, where’s the equipment to provide the service?

Maps, of course, are part of the answer. But detailed paper maps are heavy, expensive, bulky, outdated at printing and generally inaccessible when most needed. An approach that allows office teams and fieldworkers to exchange this data in real time — and one increasingly popular for government agencies both small and large — is to layer information atop digital maps in a geographic information system and marry the GIS to location tracking via Global Positioning System equipment.

A closer look at how a small Florida county and New York City use GIS and GPS programs offers details on making the most of these tools.

$635k - What Santa Rosa County, Fla., spent to gather and tag digital imagery for its GIS.

1,015 - The square miles of the county, home to 140,000 people.

Santa Rosa County, Fla.

Located in the Florida panhandle, Santa Rosa County lies just east of Pensacola and runs all the way north to the Alabama state line. Its 1,015 square miles house 140,000 people.

The biggest private employers are Wal-Mart and three hospitals; public schools, the federal government (Pensacola’s a big military town), and state and county agencies also have a comparatively sizable presence.

Sounds like many counties across the nation, but Santa Rosa County’s sophisticated use of GIS sets it apart. For the past five years, the county has poured data into a GIS that helps it respond to routine needs as well as emergencies.

“We jumped in at an opportune time” because lots of user-friendly tools were becoming available, says Aleta Floyd, the county information systems and GIS director. The first step was to gather digital aerial photographs of the county, correct them for scale — a process called orthorectification — and tag them for input into the database.

That cost about $635,000. The county struck a partnership with the Army Corps of Engineers and a list of approved subcontractors, Floyd says. The result was a map with 2-foot pixel detail. To cover its GIS upkeep, the county spends $350,000 on equipment, software, salaries, and maintenance.

“The database supports all county functions: permits, addressing, emergency management, planning and zoning, public works” and others, says Val Jarvis, the county’s IS and GIS supervisor. “Most of our concentration is on streets, getting information on those for our Public Works Department, and structures, getting the physical address of each structure and if it’s residential, commercial and so on.”

Sometimes, subtleties turn out to be important. An address database, for instance, is different than a database of structures. Not all structures have addresses: An unattached garage, for instance, shares a house’s address. Vacant lots have addresses but not structures. And not all places have useful street addresses. Parks, for example, have multiple structures.

Because a database is only as good as the data is fresh, there’s a constant flow of information coming into the system. “We get daily information from our permitting department,” says Floyd. It provides GPS information for each slab when it issues a permit. “Our addressing department is putting a point out there as they create each new address — anything that will help county departments in their work.”

Some of that work, of course, is far from routine. The 911 system makes use of the GIS database, too. “Prior to GIS, there was no mapping system for the dispatchers,” Jarvis says. “It’s easier to get directions with the GIS system.”

It lets the Fire Department know where the nearest fire hydrant is and when one is out of service. “Unfortunately, we don’t have that in full service yet,” Jarvis says. “We’re just going to keep on adding more and more benefits and services as we progress.”

And “if we’re ever activated for a hurricane, which we have been, GIS plays a critical role,” Floyd adds. “You have to have GIS if you’re going to do efficient storm recovery.”

When a hurricane cut through the county, “everybody was asking for specialized maps: the Federal Emergency Management Agency, the state, search-and-rescue teams,” she recalls. “For people from out of the area, mini-maps were printed so a game plan could be devised to find the hardest-hit areas.”

Near beaches, sand had covered all the roads, and emergency workers couldn’t get to damaged properties or begin restoration. “The first thing we did was show them where the manholes and the hydrants were,” Jarvis says. “We found every single one of them but one. Crews were able to keep from causing more damage while clearing up the roads. When you start putting dots up on a map, you start to see a pattern of the track of the storm. It paints a better picture.”

To help the public, Santa Rosa also makes its GIS maps available online at

New York City

With 8 million people, New York City is spread over five counties. Obviously, it is quite a bit larger than Santa Rosa County. It uses both GIS and GPS to improve ambulance response time.

New York City’s ambulances are rarely idle. Rather than sitting in garages waiting to be dispatched, they typically are stationed on street corners. Before GPS, each ambulance would report its locations and status to a dispatch center by radio, says Paul Martin, a project manager for Northrop Grumman Information Technology. The McLean, Va., systems integrator built the dispatch system for the city. Based on the last known location of each ambulance, dispatchers would send the closest one to each call.

But because ambulances are often in transit between their stations and emergency locations, the location information changes frequently. Dispatchers often didn’t know where an ambulance was while it was moving from point to point. It was impractical to have medics check in every few minutes.

By incorporating GPS transmitters, dispatchers can track ambulances at all times. “No matter where the unit is traveling, we can update its location along the way,” Martin says. “We can look at a map and say, ‘This unit is riding right through there,’ and turn them around and send them to the incident.”

New York City is a particularly complex environment for emergency medical service and GPS. The Fire Department runs EMS, but a patchwork of agencies, including the department itself, hospitals, companies and volunteer squads provide ambulance service. The Fire Department dispatches all of the ambulances on calls, however.

“Initially, there was a debate whether the other ambulances would or wouldn’t” be part of the GPS system, Martin adds, “But the project went so well” they all have signed onto the GPS project.

$500K - What New York City spent to integrate GPS data into its ambulance dispatch system.

Real ROI - The use of the GPS dispatch is equivalent to having three to four additional ambulances per shift.

In addition, the city is famously hostile to GPS signals; in many places, the tall buildings block the view of the sky necessary for reliable transmissions. EMS needed to find reliable GPS receivers that combined normal GPS operation and accurate dead reckoning for areas where line-of-sight to the skies is blocked.

The EMS group had been looking at GPS options for some months before the project began in earnest in June 2005, when Mayor Michael Bloomberg ordered the Fire Department to bring GPS into its dispatch system within three months.

“We had been trying to get an automated vehicle location (AVL) system up and running at EMS for, I would say, 20 years,” says Carla Murphy, program director at FDNY. “Generally, when we had the money, the technology was not good enough. After that, we never had enough money — or we never had the money long enough — to get the project done. When the mayor said go, we wanted to get it up and running as fast as possible.”

The first ambulances went online two days before the deadline. The cost for the data integration ran about $500,000, Martin says. Plus, there was the outlay for the GPS radios.

For medics and dispatchers, the change has been nearly invisible. “We were able to do this in such a way that none of the user interface changed for the dispatchers, so everything looked exactly the same to them,” Murphy says. “We didn’t have to do any training. We barely had to put in new software.”

Before rolling out the new system, “we did spend a lot of time doing drive- testing in the city to discover what kind of receiver would best fit our needs,” she says. “We have to have ruggedized equipment. We came up with a drive test that had us going through urban canyons, underground areas, areas of high electronic interference, and we varied it by time of day in case interference varied throughout the day.”

Once the new dispatch system went live, the efficiencies were so compelling that the mayor ordered the Fire Department to mount GPS units on its vehicles, too. A pilot project began early this year.

The return on investment is quantifiable for the EMS team. “After the initial phase, they determined that this project was the equivalent of putting three to four more ambulances on the street per shift,” Martin says. “You’re talking a quarter of a million dollars per ambulance,” plus the personnel costs of three to four shifts per day.

Powerful Pair: GIS and GPS

Geographic information systems essentially relate databases of things to locations. One database could contain the exact latitude and longitude of building structures in a town, for instance, while another could provide the precise locations of every fire hydrant in town.

It’s the layering and combining of databases in a GIS that makes their use so applicable for government services. The location of a structure may be a good data point, but pair it with the exact location of the street and the nearest fire hydrant, and you know how much hose firefighters might need to pull in case of an emergency, says Paul Martin, a project manager for Northrop Grumman Information Technology in McLean, Va.

Combine that with a database of addresses, and it’s a good underpinning for an emergency dispatch system. Throw in a database of unrepaired potholes and nonfunctioning water mains, and it’s easy to see how handy GIS can become. Gather and track the information over a period of years and chronic infrastructure problems will reveal themselves and can then be resolved, frequently at long-term cost savings.

As handy as GIS systems are, they are most useful for things that don’t move around much. Roads and houses tend to stay put; when they don’t, GIS systems are useful in putting them back. But they don’t help keep track of things like garbage trucks or ambulances. That’s why governments use the Global Positioning System application.

GPS is a constellation of 24 satellites orbiting 12,600 miles above the Earth. Using precise timing and complex triangulation, GPS receivers on Earth can calculate something’s location and, if it’s mobile, the direction and speed it’s traveling. The Defense Department built the satellite system, and the Air Force maintains it, relying on terrestrial towers run by the Coast Guard.

When combined with GIS, GPS is an excellent tool for determining the location of things in real time — both stationary items, whose location data can add another detail layer, and moving items such as ambulances, police cars, garbage trucks and snowplows. Knowing where those are on a moment-by-moment basis can save money — and save lives.

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