Zone A is seen in orange. The city's Office of Emergency Management is updating its evacuation maps in light of new scientific data and the lessons of Hurricane Sandy.

Why the City's Flood Maps Got It Wrong

The city's evacuation zone maps used 2003 data. Some federal maps may have predicted a wider area of flooding. But scientists also made Sandy storm-surge predictions that were dwarfed when the tropical system rolled in.

Biometric scanners, in use at an increasing number of workplaces, match computer records to the geometry of a user's hand.

After WTC Attacks, More Surveillance at Work

A 2005 survey found that keystroke monitoring was used by 36 percent of companies queried. Fifty-five percent of companies perused employee e-mail messages and 76 percent tracked websites visited by employees.

First seen on the U.S-Mexican border, the NYPD now deploys Sky Watch towers as part of its crime-fighting efforts.

On Camera: Surveillance In Transit, Schools

A 1998 New York Civil Liberties Union survey identified 2,397 surveillance cameras at street level in Manhattan. In 2005, another NYCLU survey of Lower Manhattan, Greenwich Village, Chinatown and central Harlem found 4,468 cameras in those four districts alone.