An Urban Data Goldmine

New York City agencies roll out the first public applications based on a massive new warehouse of geographic data.

by / August 1, 2001
Youre jogging in New York Citys Central Park when you spot a dead crow on the grass. Back home, you visit the city health departments West Nile virus information Web page to report the sighting.

A year ago, you might have added a sentence describing where in the 843-acre park you found the possibly infected bird. This year, you locate your jogging route on a map and click the spot where the crow lay. Your input, translated into spatial coordinates, instantly updates the Health Departments database of dead birds. As more citizens enter or phone in reports, workers know exactly where to retrieve the feathered corpses for testing, and the database generates a map to help the department track the spread of the disease.

The difference between summer 2000 and summer 2001 is that the New York City Department of Health has linked its West Nile virus information system to NYCMap, an interactive geographic database that encompasses the entire city and is accurate to within one foot.

"You can see manhole covers. If you go to Yankee Stadium, you can see home plate," said Mario Merlino, director of policy and planning and head of the geographic information systems (GIS) unit at the Department of Health. With that level of detail, citizens can also precisely report standing water in which carriers of the virus -- mosquitoes -- might breed, and city workers can identify duplicate reports so that they dont drive out twice to treat the same puddle with larvacide.

Piling Up Data
New York has spent the past seven years developing NYCMap (pronounced "nice map") as a common, highly accurate platform for geographic data maintained by city agencies. Some agencies already use it internally. But its only now that ordinary citizens have been able to see its benefits first hand. The West Nile virus-reporting form is one of the first public applications tied to the database, but many more will follow.

NYCMap was born in the citys Department of Environmental Protection (DEP), which wanted to link digital maps of the citys water and sewer infrastructures to a map of physical features. The result would show precisely where the water and sewer facilities stood in relation to one another and to points on the earth.

The concept soon broadened. "Once you created an accurate physical base map, it made sense to consider having that as the standard for the whole city, for any map-making activity," said Alan Leidner, director of citywide GIS at the New York City Department of Information Technology and Telecommunications (DoITT). By linking all of its maps to the base map, the city government could "start to build a GIS data utility, where all the citys graphical and attribute geographic information could be piled up and used interchangeably."

The base map, developed from approximately 7,500 aerial photographs encompassing the entire city, took about three years to complete. It includes an orthophotographic view -- a processed and digitized version of the photos fused into a seamless map -- and a planametric view -- an array of planes and outlines so detailed that one can see individual spaces in a parking lot. Every point on the map matches its position on the earth to within two feet, and the distance between any two points on the map is accurate to within one foot.

Although the base map charts the lay of the land in exquisite detail, it is merely a picture without data from other sources. To add intelligence to NYCMap, city agencies are busy aligning their own geographic data to the foundation.

City Planning, for example, is registering its large and well-established database of street centerlines, address ranges and related information to NYCMap. That project should be finished next spring, according to Richard Steinberg, director of geographic systems at the citys Department of City Planning. A contractor has nearly finished lining up the departments tax parcel database with NYCMap.

DEP is registering its water main data to the base, said Wendy Dorf, DEPs GIS coordinator. It recently hired a firm to develop the digital sewer line map and link it to NYCMap.

New Yorks Transit Authority is adding subway and bus lines, and Consolidated Edison, the local energy utility, will register its infrastructure to the base, Leidner said. The city is encouraging other utilities with underground facilities to add their data. When that is done, "we will have a mechanism that will not only coordinate capital improvements and infrastructure management, maintenance and repair, but also would be a good tool for economic development," he said.

Maps vs. Rats
As more organizations add their layers to NYCMap, it becomes possible to cross reference data from different sources. "You begin to consolidate the data thats available for any particular building or structure," said Michael Berkowitz, planning division supervisor at the Mayors Office of Emergency Management (OEM).

Such consolidated data has, for one thing, helped the city fight rats. As head of a rodent control task force, OEM coordinates extermination programs conducted by multiple city agencies. "Being able to do pin mapping of complaints and exterminations, and look at complaints versus exterminations - over some sophisticated mapping has allowed us to get a better handle on the project," Berkowitz said.

Someday, NYCMap will help quickly route city police, firefighters and other emergency responders to the scene when they are called to help outside their own neighborhoods, said Richard Sheirer, OEMs director. DEP also expects the map to help it move faster in emergencies. City employees already know how to locate underground valves, hydrants and other equipment, but NYCMap will help them find those facilities more efficiently, Dorf said.

At City Planning, planners use NYCMap data to create maps for zoning studies and graphics for presentations and publications. Also, planners conducting technical reviews often get the information they need from the detailed image files, reducing the need for site visits, Steinberg said.

The city stores NYCMaps central database on DoITTs IBM S/390 mainframe in a spatial data warehouse built with technology from Oracle Corp. DoITT has distributed copies of the database to city, state and federal agencies on compact discs, and it is working on a method for direct server-to-server distribution, Leidner said.

E-Gov Applications
The city is also working out policies for selling selected data from NYCMap to non-government users. "We hope to make the data available to real estate firms, architects, engineers -- people who will find the map a benefit and will benefit the city by using it," Leidner said.

But for the general public, an important pipeline for NYCMap data will be a series of e-government applications accessed through the citys Web portal.

Along with the West Nile virus reporting form, the public can see NYCMap in action in a new application on OEMs Web site that offers a guide for emergency evacuations. If a hurricane targets the city, for example, a resident can enter his address to learn if he lives in an evacuation zone. If he does, the site will show him the fastest and safest ways to travel to a public shelter by bus, subway or auto.

This fall, the city expects to debut EveryOne Map, an online view of the base map meant to educate and entertain the curious. Users will be able to see as many as 20 layers of information and perform simple analyses, perhaps checking assessed property values or examining neighborhood demographics based on U.S. census figures.

Although the EveryOne Map will allow citizens to enjoy the geographic data their tax dollars have paid for, New York has invested time and money in NYCMap largely because it will help public safety agencies save lives, Leidner said. The city also stands to save a great deal of money by better coordinating the efforts of its agencies, he added.

So far, New York has spent more than $25 million on projects associated with NYCMap. "The city would not risk that money on something it did not believe could yield major results," Leidner said.
Merrill Douglas Contributing Writer