GIS Tracks a Moving Target

A pilot flying over the edge of a wildfire in Southern California concentrates on keeping the helicopter over the advancing line of flames 50 feet below. In the passenger seat, an observer watches for hazards -- power lines, aerial tankers, other helicopters. In the back seat, a fire management officer with a pocket-sized computer/GPS system enters the locations of ground units, burning and threatened structures and logging roads. The input data appear on the display as color-coded symbols, along with the line of fire and the current position of the helicopter. As the craft reaches its starting point on the perimeter, the map line closes to form a polygon. With the perimeter completed, the crew, one of several tactical GIS teams, returns to the situation analysis mapping center (SAMC) where the data is loaded directly into a computer and printed out on maps.

Tactical Mapping
At the SAMC, incident commanders go over the new map, assess the fires current speed and direction, the topography of the area it is moving into and the location of access roads. The map will assist them in making strategic decisions -- deployment of ground and air resources, structures to be saved and areas to be evacuated.

Scenarios similar to this took place during the Viejas wildfire that struck the mountainous region of San Diego County, Calif., in January 2001. Fanned by 65 mph winds, the fire burned 10,353 acres of the Cleveland National Forest, destroyed homes and forced the evacuation of hundreds of residents. It took 2,000 firefighters, 225 engine companies and several air tankers six days to control the fire.

GIS had a key role in suppressing the Viejas fire, according to Tom Patterson, fire management officer at Joshua Tree National Park in California. "The information we were providing to incident commanders in near realtime was critical for tactical decisions," said Patterson, who was a member of the tactical mapping team for the Viejas fire.

Maps are essential tools in fighting wildfires. They provide incident commanders with the information needed to deploy resources, track the speed, direction and perimeter of the fire, assure the safety of firefighters and plan evacuation routes. Given the rapidly changing conditions associated with this type of fire, the need for up-to-date topographic and planimetric information about an area is especially critical for resource deployment in the early stages. "Knowing where your resources are is the key to safety during any fire suppression activity," Patterson said.

In the past, just collecting the data to develop a map of a fire area could take several days. By then, a fire could have progressed beyond the area covered by the data. Today, GIS units turn out area maps in minutes. Tactical GIS teams collect fire perimeter data and transmit it to a SAMC in realtime, or have it in the hands of incident commanders within a couple of hours. For the past decade, standard equipment for the task has been laptops, separate GPS receivers and cell phones, along with cables, adapters and spare batteries. Managing all this while bouncing around in a helicopter has never been easy, particularly while observing and entering data about a fast-moving fire.

New Technologies Measure Up
In the Viejas fire, teams used ArcPad, an intuitive GIS, running on Compaqs iPAQ and Hewlett Packards Journado personal digital assistants. Each was cabled to a Garmin GPS III Plus receiver. According to Patterson, the combined package weighed one pound and fit into the pocket of a flight suit.

Patterson said Viejas was the first time the group had mapped a fire using PDAs. "The ArcPad software integrates both mapping and GPS functions so that position information is automatically displayed as moving crosshairs on an actual map, rather than as numerical coordinates. We could zoom in on the map and see our position very clearly and in realtime."

Bob Bower, a resource information specialist with the Bureau of Land Management, and member of the tactical mapping team on the Viejas fire, said the GIS software draws the perimeter without manual input. "We tell it to start a polygon file, then each time it receives a position, it advances the perimeter line. When we tell it to stop editing, it closes the polygon by zapping a line from our last position to our beginning point on the perimeter."

As the perimeter is being drawn, the observer is also entering fire area information -- lines and points in a shape file -- using either a keyboard or handwriting recognition software. Structures fully engulfed, threatened structures or those 10 miles from the fires front are each indicated on the display by different colored symbols. Bower said that since the GIS software runs on desktops and laptops as well as on PDAs, the information can be transferred directly to SAMC desktops.

Wireless Improvements
Bower said his group did not use wireless modems in the Viejas fire because transmission between the helicopter and the tactical center requires an ArcIMS server site. "We dont have that yet. Also, were out in the boondocks and dont have wireless access yet to the Internet."

According to Patterson, ArcPad 6.0, which was due in July, will not only enable tactical GIS teams to transmit their position wirelessly, it will also allow them to receive data from other sources transmitting their positions. "The ideal situation is to have all division supervisors and operations staff hiking the fire line carrying wireless PDAs in their packs. Think of the tactical value -- being able to see where the fire is going, the resources coming to assist you and the locations of all your ground crews."

Patterson cautions that, despite the effectiveness of the system, ground truthing is still necessary and field observers are still needed to confirm the actual location of the fire. Still, GIS holds huge potential for future firefighting endeavors.

"GIS is in the forefront of fire fighting technology today," Patterson said. "Everyone Ive talked to says that in a few years it will be a tool as common as fire engines, hose nozzles and shovels."

Bill McGarigle is a writer specializing in communications and information technology. He is based in Santa Cruz, Calif.