Identification_Information:
Citation:
Citation_Information:
Originator: U.S. Environmental Protection Agency/Office of Water/OST
Publication_Date: 19980227
Title: Counties and County Equivalents Boundaries in the United States for BASINS
Publication_Information
Publication_Place: Washington DC
Publisher: US EPA
Online_Linkage: http://www.epa.gov/waterscience/basins/
Description:
Abstract:
This coverage is of the county boundaries of the conterminous United
States. It was derived from the U.S. Geological Survey State Boundaries,
which were derived from Digital Line Graph (DLG) files representing the
1:2,000,000-scale map in the National Atlas of the United States.
Purpose:
This coverage is intended as a basemap for a variety of applications.
Supplemental_Information:
Limitations_of_Data:
The original files for this map were provided in 15 sections.
Boundaries near the edges of sections have been adjusted in
edgematching.
Procedures:
The BASINS data product was derived from the U.S. Geological Survey
COUNTIES2M layer. The USGS procedures for that data product are followed
by the BASINS procedures:
This series of maps was published as part of the National Atlas of
the United States (USGS, 1970). The maps for the conterminous
United States were digitized in 15 sheets and published in the
Digital Line Graph (DLG) format as described by Domeratz and others
(1983).
Each sheet was prepared by reading the DLG files of the political
and water bodies layers, converting them to ARC/INFO, extracting
the county boundaries and the coastline, respectively, and joining
the two layers together. FIPS codes were assigned to all polygons
using available sources, and were checked manually.
Boundaries with adjacent sheets of the 15-sheet set were
edgematched manually, arbitrarily choosing one of the sheets as the
"correct" border. Edgematching operations adjusted the linework as
far as was necessary so that the coverages would fit to a tolerance
of 100 meters. The coverage (referred to herein as Version 1.0)
was stored as 49 separate coverages (48 states and the District of
Columbia) because the ARC/INFO software in use at the time could
not process the entire coverage. Individual states could be joined
by specifying a tolerance of 100 meters.
From time to time, adjustments were made to the state coverages to
reflect changes in U.S. counties. It is believed the accuracy of
these adjustments is comparable to the original linework.
For Version 2.0, all state coverages were rejoined and manually
edited to produce a perfect edgematch between all states. For
states on the original map sheet boundaries, this adjustment
averaged less than 20 meters and in no case was more than 100
meters. The whole coverage was CLEANed to a tolerance of 20
meters, which resulted in few, if any, effects on small offshore
islands. The coverage also was checked to ensure that it
represented current U.S. counties or county equivalents.
The coverage in Version 1.0 stopped at the coastline. There was no
attempt to depict offshore areas. The created some problems when
the coverage was used to assign county codes to sampling stations
located near the coast. To help in this matter, Version 2.o
includes offshore extensions of the county polygons. The (water)
boundaries of many of these polygons are arbitrary.
The Canadian Great Lakes features are another new addition to
Version 2.0. They were added to improve the utility of the
coverage for visual displays. Although the Canadian Great Lakes
are logically represented by a single polygon, practical
considerations -- the inability of some software to plot polygons
with a large number of vertices -- made it necessary to separate
them into 4 polygons. The dividing lines are located in narrow
channels to minimize interference with plotting patterns. Canadian
islands within the Great Lakes also were included.
All tics were relocated to places that are easily visible on maps
of the United States, to help in registering maps that may not
otherwise have adequate registration information.
To expedite accessing parts of the coverage, certain items have
been indexed with the procedure, index_county.aml. See Section 3
above. A spatial index also was created.
When using this coverage to clip or intersect other coverages, a
tolerance as low as 2 meters can be used.
The processing used to derive this coverage moved boundaries from
their positions on the original maps. In cases of conflicting
lines, preference was given to forming the correct topology.
Strictly speaking, this coverage is not identical to the source
materials. These changes were unavoidable in producing a
continuous coverage of the conterminous United States.
For revision 2.1, it was necessary to alter about 100 arcs. This
was accomplished with ARCEDIT using the 1:100,000 TIGER county
coverage as a background. These arcs were matched to the background
so that they matched at least as close as other arcs that were not
edited.
For distribution with BASINS v1.0, the national coverage was split into
a series of coverages that included the spatial extent of each of the nine
US EPA regions, plus the hydrologic accounting units that crossed Region
boundaries. The nine regional coverages therefore overlapped at
Regional boundaries. The coverages were distributed in PC ARC/INFO
coverage format.
For distribution with Basins v2.0, the PA ARC/INFO coverages were exported
on a PC then imported in workstation ARC/INFO v7.0.4. Each Regional coverage
was then projected to geographic decimal degrees, NAD83. The coverages
were then converted to ESRI Shapefile format, using the ARCSHAPE command.
Reviews_Applied:
This coverage has received no formal review. It has, however, been
used in numerous applications where serious errors would have been
obvious. Some county coverages were corrected following such use.
The offshore polygon extensions and the Canadian Great Lakes
polygons have had no review.
BASINS v2.0 reviews: projected coverages were checked for topology. The
shapefile format features and attributes were visually inspected and
compared with the BASINS v1.0 PC ARC/INFO coverages.
Other_Related_Data_Sets:
This coverage was derived from USGS 1:2,000,000-scale basemaps
covering the United States.
References_Cited:
Negri, M. Digital map of state boundaries of the conterminous
United States. 1994. U.S. Geological Survey, digital map.
Domeratz, M. A., Hallam, C. A., Schmidt, W. E., and Calkins, H. W.,
1983. USGS Digital Cartographic Data Standards: Digital Line
Graphs from 1:2,000,000-scale Maps. U.S. Geological Survey
Circular 895-D, 38p.
U. S. Geological Survey, 1970. National atlas of the United States
of America: Washington D.C., U. S. Geological Survey, 417p.
Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 1994
Currentness_Reference: publication date
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -125.0000
East_Bounding_Coordinate: -66.0000
North_Bounding_Coordinate: 50.0000
South_Bounding_Coordinate: 24.0000
Keywords:
Theme:
Theme_Keyword_Thesaurus: None
Theme_Keyword: County boundaries
Place:
Place_Keyword_Thesaurus: Geographic Names Information System
Place_Keyword: Conterminous United States of America (CONUS)
Place_Keyword: Alabama AL
Place_Keyword: Arizona AZ
Place_Keyword: Arkansas AR
Place_Keyword: California CA
Place_Keyword: Colorado CO
Place_Keyword: Connecticut CT
Place_Keyword: Delaware DE
Place_Keyword: District of Columbia DC
Place_Keyword: Florida FL
Place_Keyword: Georgia GA
Place_Keyword: Idaho ID
Place_Keyword: Illinois IL
Place_Keyword: Indiana IN
Place_Keyword: Iowa IA
Place_Keyword: Kansas KS
Place_Keyword: Kentucky KY
Place_Keyword: Louisiana LA
Place_Keyword: Maine ME
Place_Keyword: Maryland MD
Place_Keyword: Massachusetts MA
Place_Keyword: Michigan MI
Place_Keyword: Minnesota MN
Place_Keyword: Mississippi MS
Place_Keyword: Missouri MO
Place_Keyword: Montana MT
Place_Keyword: Nebraska NE
Place_Keyword: Nevada NV
Place_Keyword: New Hampshire NH
Place_Keyword: New Jersey NJ
Place_Keyword: New Mexico NM
Place_Keyword: New York NY
Place_Keyword: North Carolina NC
Place_Keyword: North Dakota ND
Place_Keyword: Ohio OH
Place_Keyword: Oklahoma OK
Place_Keyword: Oregon OR
Place_Keyword: Pennsylvania PA
Place_Keyword: Rhode Island RI
Place_Keyword: South Carolina SC
Place_Keyword: South Dakota SD
Place_Keyword: Tennessee TN
Place_Keyword: Texas TX
Place_Keyword: Utah UT
Place_Keyword: Vermont VT
Place_Keyword: Virginia VA
Place_Keyword: Washington WA
Place_Keyword: West Virginia WV
Place_Keyword: Wisconsin WI
Place_Keyword: Wyoming WY
Access_Constraints: None
Use_Constraints: None
Native_Data_Set_Environment:
ArcView shapefiles for Windows 95 PC
Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Geographic:
Latitude_Resolution: 0.0001
Longitude_Resolution: 0.0001
Geographic_Coordinate_Units: Decimal Degrees
Geodetic_Model:
Horizontal_Datum_Name: North American Datum of 1983
Ellipsoid_Name: Geodetic Reference System 80
Semi-major_Axis: 6378137
Denominator_of_Flattening_Ratio: 298.257
Entity_and_Attribute_Information:
Detailed_Description:
Entity_Type:
Entity_Type_label: CNTY.SHP
Entity_Type_Definition: County polygon attributes
Entity_Type_Definition_Source: USGS
Attribute:
Attribute_Label: SHAPE
Attribute_Definition: ArcView internal field
Attribute_Definition_Source: Computed
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: Polygon
Enumerated_Domain_Value_Definition: ArcView internal field
Enumerated_Domain_Value_Definition_Source: Computed
Attribute:
Attribute_Label: AREA
Attribute_Definition: Area of polygon in square coverage units
Attribute_Definition_Source: Computed
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: -
Enumerated_Domain_Value_Definition: Area of polygon
Enumerated_Domain_Value_Definition_Source: computed
Attribute:
Attribute_Label: PERIMETER
Attribute_Definition: Perimeter of polygon in coverage units
Attribute_Definition_Source: Computed
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: Positive real numbers
Enumerated_Domain_Value_Definition: Perimeter of polygon
Enumerated_Domain_Value_Definition_Source: computed
Attribute:
Attribute_Label: CNTY_
Attribute_Definition: Internal feature number
Attribute_Definition_Source: Computed
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: -
Enumerated_Domain_Value_Definition: Internal feature number
Enumerated_Domain_Value_Definition_Source: computed
Attribute:
Attribute_Label: CNTY_ID
Attribute_Definition: User-assigned feature number
Attribute_Definition_Source: User-defined
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: -
Enumerated_Domain_Value_Definition: User assigned feature number
Enumerated_Domain_Value_Definition_Source: USEPA
Attribute:
Attribute_Label: FIPS
Attribute_Definition: County FIPS code
Attribute_Definition_Source: FIPS
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: 01001-56999, none=0
Enumerated_Domain_Value_Definition: County FIPS numeric code
Enumerated_Domain_Value_Definition_Source: FIPS
Attribute:
Attribute_Label: ST
Attribute_Definition: 2 character state abbreviation
Attribute_Definition_Source: FIPS
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: Two characters
Enumerated_Domain_Value_Definition: State FIPS alphabetic code
Enumerated_Domain_Value_Definition_Source: FIPS
Attribute:
Attribute_Label: CNTYNAME
Attribute_Definition: County name
Attribute_Definition_Source: USGS GNIS
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: alphabetical
Enumerated_Domain_Value_Definition: County name
Enumerated_Domain_Value_Definition_Source: USGS
Attribute:
Attribute_Label: PLYTYPE
Attribute_Definition: Polygon type
Attribute_Definition_Source: See Procedures
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: 0-4 and 9
Enumerated_Domain_Value_Definition: Polygon type
Enumerated_Domain_Value_Definition_Source: USGS
Attribute:
Attribute_Label: WORKB
Attribute_Definition: Basins Internal field
Attribute_Definition_Source: USEPA
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: integer
Enumerated_Domain_Value_Definition: Basins Internal Field
Enumerated_Domain_Value_Definition_Source: USEPA
Attribute:
Attribute_Label: STCOFIPS
Attribute_Definition: State and county FIPS code
Attribute_Definition_Source: FIPS
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: -
Enumerated_Domain_Value_Definition: State and county FIPS code
Enumerated_Domain_Value_Definition_Source: FIPS
Attribute:
Attribute_Label: BEXT
Attribute_Definition: Basins internal field
Attribute_Definition_Source: USEPA
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: -
Enumerated_Domain_Value_Definition: BASINS Internal field
Enumerated_Domain_Value_Definition_Source: USEPA
Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: USEPA/Office of Water/OST
Contact_Address:
Address_Type: Mailing Address
Address: 1200 Pennsylvania Ave., NW (4305T)
City: Washington
State_or_Province: District of Columbia
Postal_Code: 20460
Country: USA
Contact_Voice_Telephone: 202-566-0400
Contact_Facsimile_Telephone: 202-566-0409
Contact_Electronic_Mail_Address: basins@epa.gov
Distribution_Liability:
Although these data have been processed successfully on a computer
system at Tetra Tech, Inc., no warranty expressed or implied is
made regarding the accuracy or utility of the data on any other
system or for general or scientific purposes, nor shall the act of
distribution constitute any such warranty. This disclaimer applies
both to individual use of the data and aggregate use with other
data. It is also strongly recommended that careful attention be
paid to the contents of the metadata file associated with these
data. The U.S. Environmental Protection Agency nor Tetra Tech,
Inc. shall not be held liable for improper or incorrect use of the
data described and/or contained herein.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: Environmental Systems Research Institute (ESRI)
ArcView Shapefile
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name: http://www.epa.gov/waterscience/basins/
Offline_Option:
Offline_Media: CD-ROM
Recording_Format: ISO 9660
Fees: None
Ordering_Instructions:
When requesting data by phone or mail, please inquire about
spatial data sets that work with Better Assessment Science
Integrating Point and Nonpoint Sources (BASINS). The BASINS web
page has instructions for downloading datasets. It also has a
link to The National Center for Environmental Publications and
Information (NCEPI), from which BASINS CD-ROMs may be ordered.
Each CD-ROM contains the BASINS v2.0 Application and this data
set along with others covering the spatial extent of an EPA
Region.
Metadata_Reference_Information:
Metadata_Date: 20070611
Metadata_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: USEPA/OW/OST
Contact_Address:
Address_Type: Mailing Address
Address: 1200 Pennsylvania Ave., NW (4305T)
City: Washington
State_or_Province: District of Columbia
Postal_Code: 20460
Country: USA
Contact_Voice_Telephone: 202-566-0400
Contact_Facsimile_Telephone: 202-566-0409
Contact_Electronic_Mail_Address: basins@epa.gov
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: 19940608