A funny thing happened while backers and critics of a proposed Major League Soccer stadium were battling over 13 acres of Flushing Meadows-Corona Park. Three hundred and fifty eight acres of the heavily used park seemed to disappear.

Over the last three years, the New York City Department of Parks and Recreation has been remeasuring every park in the system — from tiny South Oxford Park in Brooklyn to the behemoth Pelham Bay Park in the Bronx — using mapping software and satellite technology, rather than relying on a cartographer whose maps drew on city records dating to the 19th century.

The aim was to learn the size of each of the city’s 1,700 parks down to the thousandth of an acre, said Joshua Laird, a parks official who left the agency this week for the National Park Service. “We recognized for some time that our acreage tallies were fuzzy,” Mr. Laird said.

But along the way, there have been winners and losers. In Manhattan, Fort Washington Park is 24 acres bigger than previously believed, while East River Park shed 11 acres, and the already tiny Thomas Paine Park downtown lost 0.049 acres.