July 17, 2001 By Bill McGarigle
His experiences in Idaho made Anderson realize how underutilized GIS was for emergency preparedness in his own city. Up to that time, he had given little thought to Fremonts GIS unit in terms of developing emergency applications. "They do a variety of work, although not typically for emergency services," Anderson said. "We could have them producing maps ahead of time that would enable us to better respond to major disasters."
The first opportunity to use GIS in managing a potential crisis wasnt long in coming; in 2000, Fremont was hit with the first of several rolling blackouts, many of which came without warning. A city of nearly 100 square miles on the southeast side of San Francisco Bay, Fremont lies across major north-south highways running between San Jose and Oakland. Power outages at traffic signals along these arteries can result in accidents, pile ups and blocked emergency vehicles. Also at risk are critical facilities, including kidney dialysis centers, water district pumping stations, schools, office buildings with elevators, hazardous materials companies and pipelines transporting explosive liquids.
Since Pacific Gas & Electric schedules blackouts sequentially by circuit block, knowing the next block to go down and the section of the city it covered could enable Fremonts Emergency Operations Center (EOC) to move resources and personnel into the area ahead of time to direct traffic, put up stop signs and barriers and set up portable generators to power traffic lights at critical intersections. Knowing the next area to go down could also assist the EOC in establishing alternate routes for emergency vehicles, providing backup power for critical facilities and freeing people trapped in elevators.
To more accurately predict where the next blackouts were going to be, the EOC needed maps of the city sectioned by each PG&E circuit block. According to Anderson and other members of the EOC, however, PG&E declined to release specific circuit block information. "They cited reasons of national security for withholding the information," Anderson said. "I [could] cite some local security reasons why we should have the information. So [we were] at odds."
Building a Plan
Rather than give up, the EOC developed a plan to use the citys PG&E bills to determine which circuit block each traffic signal was in. "Since we couldnt get the block information directly from PG&E, we went through a back door I dont think many people are aware of -- every traffic light has an intersection location and a PG&E bill indicating the circuit block that light is in," said Christine Frost, Fremonts GIS manager.
After collecting and manually tabulating the data on intersections and traffic signals from PG&E bills, the EOC requested the GIS group translate the data into maps. The GIS group created a point file of traffic-signal intersections and their respective PG&E blocks, then loaded the data into ArcView. Using the signal locations as the foundation, the group developed rough outlines for each of the blocks overlaid on top of a base map of the city.
The EOC also provided the GIS group with a list of critical facilities and infrastructure likely to be affected during blackouts -- schools, hospitals, nursing homes, parks and dialysis treatment centers. Hazardous materials locations and pipelines will be added later.
In addition to providing paper maps requested by the EOC, Frost saw that an interactive map application could be included in Fremonts already extensive GIS database and made available via the citys fiber-optic intranet. Using Autodesks MapGuide, the GIS unit developed a Web-based application that could be
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