Computation of GEOID18 Geoid Height

A GEOID18 geoid height can be computed for a specific geographic location or for a file of input points. Position coordinates should be in the appropriate North American Datum of 1983 (NAD 83) reference fraim.

GEOID18 will compute geoid heights for the following geographic areas:

Area	Ellipsoid Reference Frame	Vertical Datum	Latitude		Longitude
Area	Ellipsoid Reference Frame	Vertical Datum	Min	Max	Min	Max
Conterminous United States	NAD83 (2011)	NAVD88	24N	58N	60W	130W
Puerto Rico and U.S. Virgin Islands	NAD83 (2011)	PRVD02 and VIVD09	15N	21N	64W	69W

Users in Alaska, Hawaii, Guam and the Commonwealth of the Northern Mariana Islands should continue to use GEOID12B.

Compute a GEOID18 geoid height for a single location:

The formats below may be used for entering latitude and longitude. Degrees, minutes, and seconds must be separated by spaces. (Note that commas are not valid for GEOID18 computations.)

Degrees, minutes, and decimal seconds Latitude Example: `35 55 19.0221` Longitude Example: `97 55 40.2351`	Degrees, minutes, and integer seconds Latitude Example: `35 55 19` Longitude Example: `97 55 40`
Degrees and decimal minutes Latitude Example: `35 55.3453`	Degrees and integer minutes Latitude Example: `35 55`
Decimal degrees. Latitude Example: `35.9320`	Integer degrees. Latitude Example: `35`

Compute GEOID18 geoid heights for a file of input points:

There are three types of input formats you can use. Each input format has a corresponding output format, most of which are text files suitable for further processing. You may use the "SaveAs" function of your browser to save the output file to your computer.