Source contribution: The GIS program for Westchester County, New York provided this data file in response to an inquiry for a 1:24,000-scale town boundary layer for the State of New York. No metadata included with the nysmun.e00 data source. Includes state, county, city, town, and village political boundaries. Data is assumed to be 1:24,000-scale. The SWIS Code identitified polygon features down to the village level. Data is in ArcInfo coverage format in the New York State Plane Coordinate System of 1983 (NAD 83), Zone 4801. Map units are in feet.

Process description: Create NORTHEASTM (Northeast United States Political Boundary Master) - The following steps describe how an ArcInfo Coverage named NORTHEASTM was created using data sources from the states of Connecticut, Maine, Massachusetts, New York, New Jersey, Rhode Island and Vermont. All data sources were downloaded directly from State GIS Web sites with the exception of data for the State of New York, which was provide by the GIS Program for Westchester County, New York. Each data source included town (municipal or township) boundary line features compiled at 1:24,000 scale (1 inch = 2,000 feet) with the exception of data from Massachusetts, which was compiled at 1:25,000 scale. Enclosing town polygon features along the shoreline, coastline features were connected to town boundary line features in each state data source.

1. Convert Data Sources to Connecticut State Coordinate System - All data sources were converted to ArcInfo Coverage format, if necessary. Each state data source was subsequently projected to the Connecticut State Plane Coordinate System, North American Datum of 1983 (NAD 83), with map units set to feet. Following the projection, polygon and line ArcInfo Coverage feature topology was created for each state data source using the ArcInfo BUILD command. When necessary to successfully complete the ArcInfo Coverage BUILD process, the ArcInfo CLEAN command was used with DANGLE and FUZZY tolerances of 10 and 4 feet, respectively.

2. Edit Geometry of State Data Source Line Features - Line features from each state data source were copied to a separate ArcInfo Coverage for each state. Line feature geometry in each line feature state data source was visually inspected and political boundary line features extending into the waters of the Atlantic Ocean, Long Island Sound, and Gulf of Maine were deleted. Coastline features that enclosed towns along the coast and offshore islands were retained. The compiler observed inconsistencies between the individual state data sources relative to the inclusion of small coastal islands and the extent to which the coastline was defined by the (upstream) shorelines of small double line streams that flow into coastal waters. Some states included all islands along the coast or incorporated a hydrography-based shoreline that continued further upstream than in other states. These unique characteristics were preserved in each state data source with the exception of portions of the New York and Rhode Island shoreline data adjacent to Connecticut that were replaced with more accurate and complete line feature geometry from Connecticut. Otherwise, the compiler did not re-digitize or redefine coastline or island shoreline features in order to add all missing island features or apply a consistent shoreline definition across all states, for example. Each line feature data source was further visually inspected and, where necessary, feature overshoots, undershoots, and duplicates were corrected in order to ensure that all line features would properly connect to form town polygon feature boundaries in a step 8. These polygons would form land-based town areas and islands along the coast that are parts to these towns.

3. Edit Attributes of State Data Source Line Features - An attribute named DATA_SRC was added (and populated with values of "CT", "ME", "MA", "NJ", "NY", "RI", and "VT") to all features in each line feature state data source in order to retain the source of the geometry of each line feature once all state data sources combined in step 8. All other line feature attributes were deleted in each state data source. Once all state data sources are combined in step 8, a consistent attribution of state, county and town boundaries is later established in step 9.

4. Edit Geometry of State Data Source Label Points - Polygon label point features from each state data source were copied to a separate ArcInfo Coverage for each state. In each label point state data source, the location of label points was visually compared to the line features in the corresponding line feature state data source produced in step 2. Any label point that was not located inside a set of enclosing line features (to be used to form town polygon features) was deleted. These label points will be used to attribute the polygon features in step 8. In general, label points were deleted from the Connecticut and Maine data sources where political boundary line features extending into coastal waters were deleted in step 2. These label points were removed because they described areas of water associated with individual towns along the coast. Label points inside the shorelines of coastal islands were retained. Other visual checks were performed to ensure that only one label point was located within each set of enclosing line features, including islands along the coast. Each label point included town and county information as attributed by the individual state.

5. Edit Attributes of State Data Source Label Points - An attribute named STATE_COD was added (and populated with values of "CT", "ME", "MA", "NJ", "NY", "RI", and "VT") to each label point state data source in order to distinguish between States once all state data sources are combined in step 8. All label point state data sources included attributes corresponding to town (or village) numbers and town names. The compiler considered attributing the town polygon features using the FIPS55 codes available at http://geonames.usgs.gov/fips55.html, but FIPS55 code values could not be easily matched to the town numbers and names in all of the state data sources so this idea was dropped. Consequently, the compiler established an alternative approach to encoding town and county designations by mapping (transferring) original attribute values included with individual state data sources to a set common data fields. The compiler added the following common fields to each label point state data source: CNTY_FIELD, CNTY_COD, CNTY_NAME, TOWN_FIELD, TOWN_COD, and TOWN_NAME. These attributes record the field names and values used by the different states for attributing counties and towns. They establish a cross reference back to the attribution in the original data sources. For example, The TOWN_FIELD stores the name of the field used by the state to encode a town, municipality or township number. So for Connecticut, Maine, Massachusetts, New Jersey, New York, New Hampshire, and Vermont, this field is populated with the following strings: "TOWN_NO", "GEOCODENUM", "TOWN-ID", "FIPS", "KEY", "SWIS", "OSP", and "FIPS6". The TOWN_COD field was subsequently populated with the numeric values stored in these fields. And the TOWN_NAME attribute was populated from text values stored in the field used by the state to encode a town, municipality or township name. For example, the attributes for the label point for the town of Andover, Connecticut are STATE_COD="CT", TOWN_FIELD="TOWN_NO", TOWN_COD=1, and TOWN_NAME="Andover"; attributes for the town of Ansonia, Connecticut are STATE_COD="CT", TOWN_FIELD="TOWN_NO", TOWN_COD=2, and TOWN_NAME="Ansonia"; attributes for the town of Abington, Massachusetts are STATE_COD="MA", TOWN_FIELD="TOWN-ID", TOWN_COD=1, and TOWN_NAME="Abington"; attributes for the town of Barrington, Rhode Island are STATE_COD="RI", TOWN_FIELD="OSP", TOWN_COD=1, and TOWN_NAME="Barrington"; and so on. CNTY_FIELD, CNTY_COD, and CNTY_NAME attributes were similarly populated. The VILLAGE attribute was added to preserve the names of villages and borough features included with data from New York. Once these state, county and town attribute values were transferred to the set of common fields, all other attributes in each label point state data source were deleted, resulting in an identical attribute schema for all label point state data sources.

6. Append Line Feature State Data Sources - Depending on the individual state, town boundary feature geometry was either based on 1:24,000-Scale Digital Line Graphs (DLG) and Quadrangle Map files from the USGS or digitized by states from either stable-base Mylar or unstable paper copies of USGS 1:24,000-scale (or 1:25,000-scale) Topographic Quadrangle maps. Consequently, line feature spatial accuracy varies from state to state and does always closely match along state boundaries. In order to append line feature data from seven states together, it was necessary to establish rules for determining which state boundary to use. First, all data would be matched to Connecticut for two reasons - (1) it is based on 1:24,000-scale DLG data from the USGS, the best digital data source for 1:24,000-scale political boundaries, and (2) Connecticut DEP desired a regional data that with boundary information for Connecticut that was consistent with information currently in use. It was also decided that the state boundary line geometry between all other state boundaries was to be based on a complete set of line features from the most accurate state data source. The state boundaries to preserve (i.e. match or snap to) were decided upon after reviewing the data source metadata and visually comparing state data source line feature geometry along state boundaries and choosing the more accurate line work. Beginning with a copy of the data from Connecticut, individual line feature data state data sources were appended (loaded) one at time and matched to the adjacent state according to the following feature matching rules - Massachusetts was matched to Connecticut, Massachusetts was matched to Rhode Island, Massachusetts was matched to New Hampshire, Massachusetts was matched to New York, New Hampshire was matched to Maine, New York was matched to Connecticut, New York was matched to New Jersey, Rhode Island was matched to Connecticut, Vermont was matched to Massachusetts, Vermont was matched to New York, and Vermont was matched to New Hampshire. For example, when Massachusetts was matched to Connecticut, all line features from the Connecticut data source were preserved, line features from the Massachusetts data source defining the CT-MA state boundary were deleted, and all (dangling and overshooting) municipal boundary line features from the Massachusetts data source extending towards Connecticut were connected to CT-MA state boundary line features from the Connecticut data source. Note, symbolizing line features on the DATA_SRC attribute visually depicts the results of matching the seven state data sources together. Once all line feature state data sources were loaded into a single ArcInfo Coverage, they were ready to form town polygon feature boundaries for the entire region in step 8.

7. Append Label Point Feature State Data Sources - All label point state data sources were appended into a single ArcInfo, ready to be used for attributing town polygon features for the entire region in step 8.

8. Combine Data Source Line and Label Point Features - Line features and label points in the two ArcInfo Coverages created in steps 6 and 7 were combined into a third ArcInfo Coverage. ArcInfo Coverage polygon and line feature topology was established using the ArcInfo CLEAN command with DANGLE and FUZZY tolerances of 10 and 4 feet, respectively. This process generated polygon features from the line features and attributed each polygon with information from the (one) label point feature located inside each polygon. For cartographic purposes, an additional attribute named LAND_CLASS was added to polygon features and populated with values of either "Land" or "Water" to distinguish between areas of land and water both on and offshore. Note, some state data sources included a few miscellaneous polygon features representing lakes, ponds, bays and coves. An additional polygon feature was manually added (digitized) to depict a large area of water off the coast of Connecticut, Maine, Massachusetts, New Jersey, New York, and Rhode Island. For map labeling purposes, an attribute named LABEL_FLAG was added to polygon features to flag town polygon features considered large and significant enough in size to be labeled on a map with town names. Polygons designated for labeling were assigned LABEL_FLAG values equal to "True", whereas small island polygons along coast, not typically labeled with town names, were assigned LABEL_FLAG values equal to "False".

9. Attribute Line Features - For cartographic purposes, a line feature attribute named BOUNDARY was added and attributed with values of "State", "County", "Town", "Village", "Shoreline" and "Closure Line" using a combination of polygon and line feature topology relationships and manual editing techniques to populate the field. State, and County boundaries were programmatically identified and attributed by comparing the ArcInfo Coverage topological relationships of adjacent polygon attributes. For example, a single line feature between (on the left and right side of the line of) two town poygon features in different states is encoded as a state boundary line feature. A line feature that is not a state boundary line feature between two town polygon features in different counties is encoded as a county boundary feature, and so on.

Process description: Convert to GeoDatabase Feature Class format - Defined new Feature Class named Northeast_State_Line; and imported the attribute definitions, loaded features and imported metadata from Northeast_State_Line.shp shapefile.

Spatial Reference Properties for Feature Class:

Coordinate System: NAD_1983_StatePlane_Connecticut_FIPS_0600_Feet

XY Domain MinX: -1337538.17925; MaxX: 2957429.11075

XY Domain MinY: -772494.257375; MaxY: 3522473.032625

Precision: 500