COMPUTATION OF GEOID09 GEOID HEIGHT

A GEOID09 geoid height can be computed for a specific geographic location or for a file of input points. Position coordinates should be in the appropriate NAD 83 reference frame.

GEOID09 will compute geoid heights for the following areas:

Area Ellipsoid Reference Frame Vertical Datum Latitude Longitude
Min Max Min Max
Conterminous US NAD83 (NSRS 2007) NAVD88 24N 58N 60W 130W
Alaska NAD83 (CORS96) NAVD88 49N 72N 126W 188W
Hawaii NAD83 (PACP00) LOCAL TIDAL 18N 24N 154W 161W
Guam and Northern Mariana Islands NAD83 (MARP00) NMVD03 11N 18N 143E 146E
American Samoa NAD83 (PACP00) ASVD02 17S 11S 168W 174W
Puerto Rico/Virgin Islands NAD83 (CORS96) PRVD02 and VIVD09 15N 21N 64W 69W

Compute a GEOID09 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, which were valid seperators for Geoid96 computations, are not valid for Geoid09 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

For South Latitudes, place a negative symbol (hyphen) in front of the degrees.
Do not have a space between the negative symbol and the number.
Latitude Example: -13 49 50.03964    Longitude Example: 171 45 20.01753 (West)

Enter Latitude:

Enter Longitude: West East

Compute GEOID09 geoid heights for a file of input points:

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

Choose an input format:

Free Format Type 1 [explain]
Free Format Type 2 [explain]
NGS Blue Book (*80* and *86* records) format [explain]

Specify the input file (on your computer)

Specify the longitude convention for your file: Positive West Positive East

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Questions or comments on this page?

Send e-mail to Dan Roman or call (301) 713-3202.