The Massachusetts Coastal Zone (polygons) data layer was compiled by the Massachusetts Office of Coastal Zone Management to represent the Massachusetts Coastal Zone as defined by 301 CMR 21.99: Boundary Appendix. This boundary was created per the Federal Coastal Zone Management Act (CZMA) of 1972 (Public Law 92-583, 16 U.S.C. 1451-1456).

The layer is named CSTZONE_POLY. In addition, an annotation feature class contains labels for various water features and is named CSTZONE_ANNO_NAME.

The full text of Boundary Appendix can viewed at http://www.mass.gov/czm/fcrczmregs.pdf and the Coastal Zone Management Act can be viewed at http://www.law.cornell.edu/uscode/html/uscode16/usc_sup_01_16_10_33.html.

Coastal Zone Inshore Boundary: The CZ inshore boundary was created by following the verbal boundary description given in the referenced Boundary Appendix. Data sources used were: MassGIS "Executive Office of Transportation - Office of Transportation Planning Roads - April 2007" for streets and highways, MassGIS "1:5,000 Road and Rail Centerlines - October 2002" for rail line beds, and MassGIS "Community Boundaries (Towns) from Survey Points - June 2004 (last updated December 2007)" for inland town boundaries. In areas where the Appendix did not conform to current ground conditions (e.g. the Neponset River Reservation which has been expanded since the Appendix was written), georeferenced scans of property boundaries were used. Note: Per the Appendix, "...the actual boundary is 100 feet inland of the landward side of the road." Since the landward side of the road could not be determined from the EOT streets layer, a 100 foot landward buffer was created from the depicted road center line; when two lanes were shown on the EOT layer (e.g. for a divided highway), the landward-most lane was used to create the buffer.

Coastal Zone Lateral Boundaries: The MassGIS "Community Boundaries (Towns) Without Coast - October 2002" data layer was used to create the lateral offshore boundaries between Massachusetts, New Hampshire, and Rhode Island.

Coastal Zone Offshore Boundary: The CZ offshore boundary was defined by the U.S. Minerals Management Services "Digital Offshore Cadastre (DOC) - Atlantic83 - Submerged Lands Act (SLA) Boundary Line" that defines the offshore boundary between Commonwealth and Federal Jurisdiction. These data can be downloaded from http://www.mms.gov/ld/Maps.htm.

Compilation: All boundary line data were merged, trimmed, dissolved, checked for topological errors, and then converted to a polygon.