Geographic coordinates provided to the Commission via the Universal Licensing System must be referenced to the North American Datum of 1983 (NAD83). If the source from which you obtain the coordinates is referenced to another datum (e.g., NAD27, PRD40) you must convert the coordinates to NAD83.
The FCC uses the procedures outlined below when converting licensing data to NAD83 coordinates when a radio service is converted to the Universal Licensing System (ULS). In most cases, this procedure uses the NADCON software developed by the National Geological Survey. For certain Pacific island areas, the FCC uses a specified shift from the applicable local datum. For other Pacific island areas where a conversion is not yet available, coordinates should continue to be referenced to the applicable local datum.
Applicants and licensees who need to submit NAD83 coordinates to the Commission should use the conversion procedures outlined below:
Procedure for Converting Coordinates to NAD83
Methods of conversion. Sort the site data by state/territory and take the action listed below. Near-offshore sites and sites in the Gulf of Mexico are converted as part of the nearest state/territory.
|Convert using NCAT|
|CONUS (i.e., the contiguous 48 states and the District of Columbia)
Alaska (including St. Laurence, St. George, and St. Paul Islands)
U.S. Virgin Islands
|Convert to NAD83 using NCAT software
|Convert using Specialized Methods|
|American Samoa||Convert to NAD83 using Method #1 below|
|Guam||Convert to NAD83 using Method #2 below|
|Do Not Convert|
Northern Mariana Islands
Palmyra Island (Atoll of Palmyra)
|Do not convert to NAD83; coordinates remain in local datum|
The following chart summarizes the input parameters of the NADCON software. All other latitude/longitude combinations are "out of bounds" (i.e. too far offshore) and cannot be converted using the NADCON software because NAD83 is not applicable to these sites.
|Latitude (degrees)||Longitude (degrees)|
|Location||min latitude||max latitude||min longitude||max longitude|
|Puerto Rico and USVI||17||19||64||68|
|AK - St. Laurence Island||62||64||168||172|
|AK - St. George Island||56||57||169||171|
|AK - St. Paul Island||57||58||169||171|
For the unincorporated territory of American Samoa.
The following datum shift converts coordinates referenced to the American Samoa Datum of 1962 to NAD83. Determine on which island the site is located and perform the conversion as follows:
For Tutuila Island
lat, long (NAD83) = lat - 17.83406", long + 4.37866"
For the Manua Islands
lat, long (NAD83) = lat - 18.32515", long + 4.43134"
For the unincorporated territory of Guam.
The following datum shift converts coordinates referenced to the Guam 1963 datum to NAD83. Perform the conversion as follows:
lat, long (NAD83) = lat + 5.15932", long + 8.71596"
NOTE for the above methods: The FCC previously provided these datum shift coordinates rounded to two decimal places. ULS will record latitude and longitude to the tenths. We are providing the coordinate data as supplied by NGS for the benefit of licensees and applicants whose source data may consist of more than two significant digits.
Sources: The conversion information below was supplied by the National Oceanic and Atmospheric Administration, National Geodetic Survey's internet website, www.ngs.noaa.gov, and Mr. David Doyle of the NGS's Observation and Analysis Division.
In 1990, the Federal Geodetic Control Committee adopted the method employed by the NADCON software as the federal standard for the conversion to NAD83. See Notice to Adopt Standard Method for Mathematical Horizontal Datum Transformation, 55 Fed. Reg. 32681-01. We will add links to other resources as they become available and are tested by the FCC and NGS for compliance with this standard. If you are aware of other resources that may be useful in this regard, please email us.
Disclaimer: The Commission makes no warranty whatsoever with respect to the software. In no event shall the Commission, or any of its officers, employees, or agents, be liable for any damages whatsoever (including, but not limited to, loss of business profits, business interruption, loss of business information, or any other loss) arising out of or relating to the existence, furnishing, functioning or use of the software.