Data-sharing project helped New York's GIS escape disaster
- By Trudy Walsh
- Sep 09, 2002
'I wish I could say that we had a deliberate backup of the city's GIS. But we just lucked out,' Alan Leidner said.
National Oceanic and Atmospheric Administration aircraft gathered aerial images of the World Trade Center complex using light detection and ranging technology from Optech Inc. of Toronto. The Army then rendered 3-D maps of the destruction to provide detailed structural data for use in the recovery and cleanup effort.
A year ago today, Alan Leidner left his apartment on the Upper West Side a little before 9 o'clock. 'I heard someone yelling that it looked like a small plane went into the World Trade Center,' he said.
Sept. 11 was the date of a primary election in New York to vote for, among other things, a new mayor. Leidner, New York City's director of citywide geographic information systems for the IT and Telecommunications Department, walked to his polling place, which had a small TV. 'I could see the building burning on the TV there. I remember thinking, 'Whatever kind of plane that was, it sure wasn't small.' '
He went to the subway unaware that a second plane had crashed into the towers. When he got out of the subway he saw 'this huge cloud. The ash was streaming off the backs of the ambulances driving downtown,' he said.
Leidner went to his office at 75 Park Place, a few blocks from the World Trade Center, but it had been evacuated. Later, there were reports that a piece of debris from one of the airplanes had hit the office and killed two people on the ground.
'I knew that all our GIS capabilities were knocked out,' Leidner said. 'We knew that 7 World Trade Center [which housed the city's Emergency Operations Center] was abandoned, and they had the GIS setups. My office was the center of GIS for the city. I thought, 'Geez, we're pretty well knocked out of action.' 'Needle in a haystack
Leidner wandered around downtown with a respiratory protector over his nose for about two hours, trying to find where his office had relocated. He finally gave up and walked seven miles uptown to his apartment because the subway was shut down.
'I took a shower and washed all the ash off me,' he said.
Around 5 p.m. Leidner got a call from the mayor's office saying that his office had relocated temporarily to the New York City Police Academy at 235 E. 20th St., near Gramercy Park. The mayor's office also told Leidner that it needed maps right away.
Leidner's office had worked closely with the geography department of Hunter College on East 68th Street in midtown Manhattan. The college department had a complete duplicate of the city's GIS database.
'I wish I could say that we had a deliberate backup of the city's GIS,' Leidner said. 'But we just lucked out.'
By the evening of Sept. 11, Leidner and the Hunter geography staff had begun to set up an emergency mapping center at the Police Academy.
The college workers brought a PC equipped with a 150G hard drive, scaled to handle large geographic files, Leidner said.
The city's GIS, known as NYCMap, accesses an Oracle8i database of digital geographic data about the city, accurate to within 18 inches. It uses ArcInfo and ArcSDE software from ESRI of Redlands, Calif.
The city's IT and Telecommunications Department and Hunter College's Center for the Analysis and Research of Spatial Information (CARSI) had spent five years building the database. It contains thousands of aerial photographs and includes data layers detailing parks, buildings, curbs, water mains, sewers and gas lines.
Fortunately, the Police Academy had its own plotter, Leidner said. The morning of Sept. 12, Leidner and his team set up shop in a room in the academy just below the Emergency Operations Center's temporary room. 'We put up a sign that said 'Mapping,' and we started to take orders,' Leidner said.Orders, please
The Parks Department, which had escaped the disaster relatively intact, dropped by with seven PCs. 'We started to crank out stuff'utility outage maps, city printouts,' Leidner said. 'We got a rudimentary order system going. We went on the Internet and got some imagery from satellites and some aerial photographs.'
Then Leidner got word that the makeshift mapping office would be moving to offices at Pier 92 on the Hudson River at 52nd Street. 'I asked the mayor's office for 25 PCs with plotters. They said OK.'
By Saturday, Sept. 15, Leidner's group had moved to the offices on the pier and set up a working network.
'That first week we got 100 requests for GIS information,' Leidner said. 'In the second week, we responded to 1,000 requests for GIS data.' Demand for maps and GIS information was insatiable.
Leidner stressed the importance of interoperability, standards and cooperation among agencies. 'We had been building our data to U.S. Geological Survey and Open GIS Consortium standards,' Leidner said. 'If you're on a common map, basically your data will talk.'
Leidner and the GIS office have moved five times in the past year: the Police Academy, Pier 92, midtown offices, back to 75 Park Place, and finally 59 Maiden Lane near the southern tip of Manhattan.
Leidner said the attacks on the World Trade Center renewed his dedication to building the city's GIS capabilities. 'This stuff is life and death,' he said. 'We sort of knew that, but Sept. 11 brought home our vulnerability. We need GIS data to be there in an emergency.'
Trudy Walsh is a senior writer for GCN.