Back to State Plane Coordinate System - Designations

Revisions: 8/13/1999
(1) Broome County, NY moved from East Zone to Central Zone as per NOAA Manual NOS NGS 5
(2) Park County, WY added exception of Yellowstone National Park, which is included with the West Zone
(3) Grant County, WA added to both zones to indicate zone split at 47°30'
(4) Montana added clarification between NAD27 and NAD83 systems
(5) Los Angeles County, CA added note to clarify designation between NAD27 and NAD83.
Revisions: 8/23/1999
(1) Nebraska and South Carolina differentiated North and South Zones as per "Index of State Plane Coordinate (SPC) Zone Code Map"
U.S. Dept. of Commerce, NOAA, NOS, Dated August 1982
Revisions: 1/10/2001
(1)Corrected UTM Zone designation for Hawaii Zone 3 Honolulu County to Zone 4 from Zone 3.
(2)Revised County designation for Hawaii Zone 5 to reflect that it actually lies within Kauai County.
Revisions: 7/06/2001
(1)Updated URL for NGS Data Sheets.
Revisions: 8/20/2002
(1)Eliminated Code URLs
Revisions: 10/17/2003
(1)Fixed Link to Census Places Files
(2)Added Links to spc.gif
(3)Added Link to download SPC Zone Excel Spreadsheet
Revisions: 07/11/2004
(1)Revised the County Designation for New York East Zone and New York Island Zone, moving Bronx and New York counties to the New York Island Zone according to their actual usage and aggregation with the other New York City counties.
Revisions: 12/12/2004
(1)FIPS6-4 Change Notice 2 12/21/1992: Yakutat Borough,AK created FIPS CODE 282; Skagway-Yakutat-Angoon, AK Census Area FIPS CODE 231 (deleted) renamed Skagway-Hoonan-Angoon, AK FIPS CODE 232 (added).
(2)FIPS6-4 Change Notice 3 05/25/1995: Independent City of South Boston, VA reverted to town status FIPS CODE 780 deleted.
(3)FIPS6-4 Change Notice 4 07/19/1999: Yellowstone National Park, MT is legally part of Gallatin and Park Counties FIPS CODE 113 deleted.
(4)FIPS6-4 Change Notice 5 07/22/1999: Dade County, FL changed its name to Miami-Dade County, FL FIPS CODE 025 deleted FIPS CODE 086 added.
(5)FIPS6-4 Change Notice 6 01/24/2002: Broomfield County, CO created from parts of Adams, Boulder, Jefferson and Weld counties FIPS CODE 014 added.
(6)FIPS6-4 Change Notice 7 07/07/2001: Independent City of Clifton Forge, VA reverted to town status FIPS CODE 560 deleted.
Revisions: 03/02/2005
(1)Corrected UTM Zone designation and Lat/Long values for Honolulu HI.

Purpose:
The purpose of the State Plane Coordinate Systems - Designations Web Page is to provide a reference tool to aid the identification of a coordinate system applicable to a particular digital dataset. It is most useful in selecting reasonable candidate "systems", from which to obtain X,Y coordinate values, which can then be compared with those in the dataset.

Research:
In the 1930's, the U.S. Coast and Geodetic Survey, designed coordinate systems for each of the states based on the North American Datum of 1927. The states were then tasked to adopt the appropriate legislation enabling the use of these systems by official reference. Their use, however, was not mandatory.

There is inherent, with all coordinate transformations utilized for geo-mapping, a degree of distortion between objects located on the Earth with their representations depicted on a 2-dimensional plane . This distortion was minimized in the State Plane Coordinate System by breaking larger states into smaller zones consisting of aggregate groups by County. The assignment of a County to a particular zone is contained in the State Statutes, with most states enacting similiar legislation. With the development of the North American Datum of 1983, many states modified the statutes for their system to include the new datum. The nature in which this modification was made varied from state to state. Some merely included the new datum, others abandoned the older datum, still others changed to one zone. In order to provide a more comprehensive listing of the State Plane Coordinate System, its zones and County assignments, I set out to research each states' Coordinate System legislation.

The availability of searchable legal databases on the World-Wide Web provided access to the Codes of most of the states, so this is where I began. There were states that did not have their State Code online, and in those instances another method was utilized to identify the appropriate system for each county.

I have included the following table reflecting the results of my search for the state code which defines the State Coordinate system. The Code Reference is the numerical index to the Title, Chapter or Section of where the Coordinate System statute is located. The URLs, which linked to the particular sections of code, have been removed as many of them were broken

The legal research on the web was conducted from 2/1999 thru 3/1999. The URL's are probably static and subject to change.

For states that were not searchable online, geographic coordinates for the county were obtained from the U.S. Census Bureau's "counties.txt" dataset obtained from:
http://www.census.gov/tiger/tms/gazetteer/counties.txt-1990 Census Gazetteer and
http://www.census.gov/tiger/tms/gazetteer/county2k.txt-2000 Census Gazetteer

The geographic coordinates were then converted from decimal degrees to Degrees-Minutes-Seconds and were used to locate an NGS data sheet with control point information from this location:

http://www.ngs.noaa.gov/cgi-bin/ds_radius.prl

Generally, each control point with the data sheet is identified with Lat/Long, UTM and State Plane coordinates. The state plane zone displayed being within its appropriate zone.

Validation:
The NOAA Manual NOS NGS 5, titled "State Plane Coordinate System of 1983", was used to compare my results. The discrepancies are noted as follows:

Broome County, NY, is clearly shown to be aggregated within the Central Zone, as depicted in the Manual. Originally, I had associated this county with the East Zone based upon control point references from NGS. A 3-hour expedition thru the NY Code failed to disclose the whereabouts or the existence of any Coordinate System legislation that would provide the clarification. I chose to associate this County with the Central Zone, based upon geographical conformance with counties adjacent.

Pulaski County, AR, is clearly shown to be aggregated within the South Zone, as depicted in the Manual. I have this county included in the North Zone based on the Coordinate System legislation ( 15-21-302 ).

Valencia County, NM, is clearly shown to be aggregated within the West Zone, as depicted in the Manual. I have this county included in the Central Zone based on the Coordinate System legislation ( 47-1-49 ). The Manual makes note of the creation of a new county in New Mexico which promulgated a zonal change, but fails to be more specific.

Accuracy:
No warranty of accuracy is guaranteed or implied. The verification of this data is in progress and additional research is being done to obtain additional reference to some of the zones. It is only a tool of reference.

Image:
The bitmap displaying the "Lower 48 Zones" was created in ArcView and further enhanced in Adobe PhotoShop.

Credit:
Special thanks to Jon Proctor with Front Range Ortho GIS Consultants, Inc. and Donna Amoroso with the NGS Info Center, for their help with Nebraska and South Carolina (NAD27) designations

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