Contents
Introduction to the Files
Downloading and Decompressing
Source Information
Attributes
Projection and Accuracy
Changes from Previous Releases

Each borough's Tax Block geography is provided in two formats: MapInfo® Table and ArcView® Shapefile. These files are data files, not programs. The user will require a CAD (Computer Assisted Design or Drafting), mapping, GIS (Geographic Information System), graphics/drawing or other software package that can import ArcView Shapefiles or MapInfo Tables.

Information on some of these products can be found at the websites of the following: MapInfo and ESRI. The Department of City Planning does not endorse any particular product. The BYTES of the BIG APPLE files have not been tested with every package that claims to import these formats.

DCP also releases Tax Lot Base Map Files in MapInfo Tables, and ArcView Shapefile formats on CD-ROM through a license agreement. Call (212) 720-3505 for more information on the Tax Lot Base Map File license.

For each of the five boroughs of New York City, files are available in two formats for downloading: ArcView ShapeFiles and MapInfo Tables. When you select to download one of the boroughs in a particular format, you will be prompted to save a zip file on a local drive. The zip file will be named in the form:

• bcodeav.zip (for the ArcView format)
• bcodemi.zip (for the MapInfo format)

Each of the types of files has been compressed (zipped) into .Zip files. You can unzip the contents of the .Zip file. Depending on the format selected, unzipping these files will result in either:

• MapInfo - four files comprising a MapInfo table of tax blocks and four files comprising a MapInfo table of street name annotation; or
• ArcView - four files comprising an ArcView Shapefile of tax blocks and four files containing street name annotation.

Go to the Tax Block Download Page.

Map Sources: These files are derived from the Department of City Planning (DCP) Tax Block geography files. These files are digitized and maintained by the DCP Information Technology Division/Geographic Systems Section. The primary sources for these files are Department of Finance (DOF) tax maps. These files are schematic representations of the tax block outlines and should not be used for applications that require precise measurements. Please be advised that the only authoritative source for the current official tax block geography is the New York City Department of Finance. These BYTES of the BIG APPLE tax block files are not to be taken as the official representation of the City's tax block geography.

Legal vs. Physical features: These files are a representation of the City's tax blocks. Tax blocks are not identical to physical blocks. Boundaries of tax blocks are not usually located at the curb line of a street. Many blocks along the shoreline include areas under bodies of water. Most highways and many other features are not represented in these files because they are not formally part of the City's Tax Map.

Block Outlines: These are stored as polygons in the MapInfo and ArcView formats. The tax blocks are generated from the 'external' (street frontage) lot lines of all lots constituting each tax block. As a result, the line work representing a tax block will contain several intermediate points.

BoroCode: 1: Manhattan  2: Bronx  3: Brooklyn  4: Queens  5: Staten Island

Block Numbers: Tax block numbers are assigned by the Department of Finance (DOF). They consist of from one to five digits; for example, 486 and 10012 may be valid tax block numbers. Although a tax block number is unique within a borough, it may apply to two or more physical blocks. For tax blocks consisting of more than one physical block, each physical block is represented in these files as a separate object.

In very few cases, the Department of City Planning has assigned 'stand-in' tax block numbers for blocks representing tracts of land that do not have a DOF tax block number. Examples are traffic islands in the center of Park Avenue (Manhattan) and Pelham Parkway (The Bronx). In these cases, the assigned numbers are unique within a borough and are numbered to be much higher than the range of valid tax block numbers in the borough; the numbers assigned start with 20000.

In MapInfo and ArcView formats, tax block numbers are stored as attributes of the tax block polygons.

Streetnames: Street names are selectively placed throughout the Tax Block files in the form of text annotation. In MapInfo, they are included as a separate streetname table. In Shapefiles, streetnames are distributed as point features with one field containing the streetname and another field containing the text angle.

Projection and Accuracy
In the Tax Block files in MapInfo format and ArcView Shapefile format, the map projection used is the New York Long Island State Plane Coordinate System (NAD83). All coordinates in the MapInfo files are in feet.

The tax block files were created for thematic mapping purposes within the Department of City Planning. High spatial accuracy was not of primary concern in their creation. A limited set of control points was used to loosely fit the lines to the New York Long Island State Plane Coordinate System.

The New York City Tax Blocks have been conflated to the NYCMap planimetric features.

The Tax Block files are created from Release 06C of the Department of City Planning Tax Block files. They contain updates through October 2006.

• There were no significant changes since the previous release of 05D.