This polygon layer is a subset of the Census TIGER census tract file, re-projected to local state plane and modified by subtracting a subset of the Census TIGER water layer (nyu_2451_34507) from it to create land-based boundaries. Tracts are statistical areas built from census blockgroups that are designed to have an ideal size of 4,000 residents, with range of 1,200 to 8,000. The nta fields indicate the Neighborhood Tabulation Area (NTA) to which the tract belongs; NTAs are statistical areas created by the NYC Dept of City Planning for presenting census data. The unique ID is tractid; the FIPS state-county-tract number code. This layer was created as part of the NYC Geodatabase (NYC GDB) project, a resource designed for basic geographic analysis and thematic mapping within the five boroughs of New York City.