Maps to the heart of the City

Real Estate Weekly, Sept 13, 2000 by Natalie Keith

Library's map room proving invaluable to developers

A contractor is digging the foundation for a new office building when he hits an unexpected source of water.

Where can he turn to research the origin of the water? One person he might ask is Alice Hudson, Chief of the New York Public Library's Map Division.

"We've bad people come here wearing waders frying to find out why their site is wet," Hudson said during a recent interview.

Contractors and others experiencing water problems will often ask to see the 1874 Topographical Alias of the City of New York or, to those familiar with it, "the Water Map." The map delineates underground creeks, wetlands and other sources of water that may not be as easily found on modern maps, she said.

"It's over a 100 years old and people still use it," Hudson said, "The Water Map" done by cartographers Matthew Viele is one of the 405,000 maps, 18,000 atlases, and numerous cartography books contained in the Map Division located in Room 117 of the library's main branch at 42nd Street and Fifth Avenue. Established in 1898, the division focuses on New York City but contains maps from around the world dating from the 16th Century to the present.

"We have to serve the taxpayers and the audience that's here," she said.

Among the most frequently used resources are property and insurance maps, which draw a steady stream of developers, lawyers, urban planners, architects and other real estate professionals into the division. U.S. laws and regulation require builders to conduct environmental impact analyses and to assess historical value of properties prior to construction. Map libraries across the country are spending an increasing portion of their time facilitating urban ancheology and site studies.

At times Hudson has found herself at the center of a neighborhood debate over a planned development, when developers and residents have used division resources to conduct research on the proposed development site. For instance, when the West Side Highway was being debated in the mid-1980s, proponents and opponents of the project used the division.

"Both sides came in and looked at the same set of maps and came up with different conclusions," Hudson said. "(The Map Division) is neutral." New York City real estate and insurance atlases, dating back to the 1850s, make up the largest distinct collection of thematic atlases in the Map Division. Insurance companies have long been concerned about fire risk, which is the greatest threat to urban areas. In 1835, a fire destroyed much of New York City and caused many insurance companies to go out of business. Many homeowners fabricated or exaggerated loses and, because of the lack of detailed property records, insurance companies were able to fight claims.

After 1835, cartographers went to great lengths to detail structures and the materials used to build them. The first maps to contain such detail were done by William Penis from 1852 to 1857. On the maps, pink blocks delineate brick and stone structures and yellow blocks delineate frame structures. Steam generators, which pose a great fire threat, are shown on maps with black blocks.

For scholars or other interested individuals, these maps provide important clues for determining the cultural and social history of an area. The maps show porches, bay windows, horse trails, and a variety of other items that help paint a portrait of life during a particular era.

With the maps, researchers can detail elements of the city's development history and can even determine how Manhattan looked prior to 1811, when the "grid" system, with its series of numbered streets and right angled intersection, was established. The system, which was devised for areas north of Greenwich Village through state and city law, created "paper streets" which were shown on city maps. Developers and others were required to follow this system, and often had to give up portions of their land for new streets.

For those interested in learning about Manhattan geography prior to the grid system, the division has the British Headquarters map of 1782, when the British Army occupied Manhattan during the American Revolution.

Another historical phenomena that can be researched through the maps is the history of Broadway which, unlike most other city streets, cuts across the island in a diagonal pattern from east to west, intersection other streets at odd angles.

Maps delineating, the grid system did not show Broadway, which was an Indian path leading all the way to the state capitol in Albany. The street was supposed to disappear above 23rd Street, but somehow survived.

"It survived the politicians," Hudson said.

Although the division focuses on keeping historical records and maps, it has a computer mapping station. Geographic Information System software such as Atlas GIS, ArcView, Epimpa, and MundoCart are available. The Division will soon hirede planning a libraries that will specialize in GIS.

Hudson also points out that EDF Sanborn Inc. is working on establishing an electronic resource system with the Library of Congress, to make some resources available on-line.