WGS 1984 Earth Gravitational Model Metadata



Welcome to the Geospatial Sciences metadata for the World Geodetic System 1984 Earth Gravitational Model.

This metadata was written using the Content Standards for Digital Geospatial Metadata, June 8, 1994 version, and released by the Federal Geographic Data Committee

1.0 Identification Information:
basic information about the data set.
6.0 Distribution Information:
information about the distributor of and options for obtaining the data set
7.0 Metadata Reference Information:
information on the currentness of the metadata information, and the responsible party.

1.0 Identification Information:

1.1 Citation:
1.1.1 Originator: National Geospatial-Intelligence Agency
1.1.2 Publication Date: 1985
1.1.4 Title: WGS 84 EGM (complete to degree and order 180)
1.1.5 Edition: First
1.1.6 Geospatial Data Presentation Form: spherical harmonic geopotential normalized coefficients
1.1.8 Publication Information:
1.1.8.1 Publication Place: St. Louis, Missouri
1.1.8.2 Publisher: National Geospatial-Intelligence Agency
1.2 Description:
1.2.1 Abstract: This data set is a file of the WGS 84, fully normalized, earth gravity (geopotential) coefficients, complete to degree (n) and order (m) 180. These spherical harmonic coefficients are used in Clenshaw summation numerical algorithms or FFT algorithms to compute the following gravimetric quantities: point gravity anomalies, point geoid heights, point N-S or E-W components of the deflection of the vertical, point total deflection of the vertical, point radial component of the gravity disturbance vector, and point N-S or E-W component of the gravity disturbance vector. The WGS 84 model is based on the WGS 84 ellipsoid, and the coefficients are calculated from a worldwide grid of 1-degree mean free air gravity anomalies.
1.2.2 Purpose: The WGS 84 coefficients are required in the spherical harmonic equations that are used to calculate the gravimetric quantities listed above. The data from these calculations are used primarily by the DoD and their contractors to provide long wavelength models of the Earth's gravity field and geoid for various weapon systems.
1.3 Time Period of Content:
1.3.1 Single Date/Time: 1984
1.3.2 Currentness Reference: 1984
1.4 Status:
1.4.1 Progress: Complete. A new EGM complete to degree and order 360 is expected in 1996.
1.4.2 Maintenance and Update Frequency: Irregular
1.5 Spatial Domain:
1.5.1 Bounding Coordinates:
1.5.1.1 West Bounding Coordinate: -180.0 degrees
1.5.1.2 East Bounding Coordinate: 180.0 degrees
1.5.1.3 North Bounding Coordinate: 90.0 degrees
1.5.1.4 South Bounding Coordinate: -90.0 degrees
1.6 Keywords:
1.6.1 Theme:
1.6.1.1 Theme Keyword Thesaurus: DoD Glossary of Mapping, Charting, and Geodetic Terms
1.6.1.2 Theme Keyword: Earth Gravity Model, EGM 180, Geoid, Geopotential Coefficients, Spherical Harmonics, WGS 84, Harmonic Models
1.6.2 Place:
1.6.2.1 Place Keyword Thesaurus: None
1.6.2.2 Place Keyword: Worldwide
1.7 Access Constraints: All requests for this data must be made to NGA, which is the sole authorized distributor.
1.8 Use Constraints: NGA allows unlimited releasability and distribution of the WGS 84 Geopotential Model
1.9 Points of Contact:
1.9.2 Contact Organization Primary:
1.9.2.1 Contact Organization: NGA Office of Geomatics
1.9.2.2 Contact Person: Physical Geodesy Program Manager
1.9.3 Contact Position: Program Manager
1.9.4 Contact Address:
1.9.4.1 Address Type: mailing address
1.9.4.2 Address: 3838 Vogel Road L-41
1.9.4.3 City: St. Louis
1.9.4.4 State or Province: Missouri
1.9.4.5 Postal Code: 63010-6238
1.9.4.6 Country: United States of America
1.9.5 Contact Voice Telephone: (314) 263-4486 or DSN 693-4486
1.9.7 Contact Facsimile Telephone: (314) 263-4102 or DSN 693-4486
1.9.8 Contact Electronic Mail:wgs84@nga.mil
1.9.9 Hours of Service: 0900-1500 Mon to Fri (Central Time)
1.14 Cross Reference: WGS 84 (n=m=180) model is used as a part of the service titled, Geodetic Quantities from Spherical Harmonics, which is also provided by NGA Office of Geomatics. Please check the metadata listing for this service.

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6.0 Distribution Information:

6.1 Distributor:
6.1.2 Contact Organization Primary:
6.1.2.1 Contact Organization: NGA Office of Geomatics
6.1.2.2 Contact Person: Physical Geodesy Program Manager
6.1.3 Contact Position: Geodesist
6.1.4 Contact Address:
6.1.4.1 Address Type: mailing address
6.1.4.2 Address: 3838 Vogel Road L-41
6.1.4.3 City: St. Louis
6.1.4.4 State or Province: Missouri
6.1.4.5 Postal Code: 63010-6238
6.1.4.6 Country: United States of America
6.1.5 Contact Voice Telephone: (314) 263-4486 or DSN 693-4486
6.1.7 Contact Facsimile Telephone: (314) 263-4102 or DSN 693-4102
6.1.8 Contact Electronic Mail: wgs84@nga.mil
6.1.9 Hours of Service: 0900-1500 Mon to Fri (Central Time)
6.2 Resource Description: EGM180.NOR
6.3 Distribution Liability: TBD
6.4 Standard Order Process:
6.4.2 Digital Form:
6.4.2.1 Digital Transfer Information:
6.4.2.1.1 Format Name: ASCII
6.4.2.1.3 Format Version Date: 1994
6.4.2.1.5 Format Information Content: Four columns: degree, order, Cnm Snm
6.4.2.1.7 Transfer Size: 690,912 bytes
6.4.2.2 Digital Transfer Option:
6.4.2.2.1 Online Option:
6.4.2.2.1.1 Computer Contact Information:
6.4.2.2.1.1.1 Network Address:
6.4.2.2.1.1.1.1 Network Resource Name:http://earth-info.nga.mil/GandG/wgs84/
6.4.2.2.1.2 Access Instructions: Standard Internet Protocols. If desired, we are also able to upload this data set via FTP.
6.4.2.2.1.3 Online Computer/Operating System: Sun Computers/UNIX
6.4.2.2.2 Offline Option:
6.4.2.2.2.1 Offline Media: 3.5 inch floppy disk, 8mm cartridge, 9-track tape.
6.4.2.2.2.3 Recording Format: UNIX tar, UNIX dd
6.4.2.2.2.4 Compatibility Information: DOS Compatible for floppy, other media are created using UNIX commands.
6.4.3 Fees: No Fee
6.4.5 Turnaround: Two days
6.5 Custom Order Process: Customers must contact the Identification Information Section Point of contact. The WGS 84 (n=m=180) model can be ordered as a separate product in the form of the file, EGM180.NOR, or as a part of the service, Geodetic Quantities from Spherical Harmonics. With this service, a computer program is provided along with the coefficient file.
6.6 Technical Prerequisites: The user should have a familiarity with geographic information, e.g. latitude and longitude, and with MS-DOS language. Knowledge of Fortran 77 would be helpful but not mandatory.

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7.0 Metadata Reference Information:

7.1 Metadata Date: 1 December 1995
7.2 Metadata Review Date: 1 March 1998
7.3 Metadata Future Review Date: 1 March 1999
7.4 Metadata Contact:
7.4.1 Contact Person Primary:
7.4.1.1 Contact Person: Physical Geodesy Program Manager
7.4.1.2 Contact Organization: NGA Office of Geomatics
7.4.4 Contact Address:
7.4.4.1 Address Type: mailing address
7.4.4.2 Address: 3838 Vogel Road L-41
7.4.4.3 City: St. Louis
7.4.4.4 State or Province: Missouri
7.4.4.5 Postal Code: 63010-6238
7.4.4.6 Country: United States of America
7.4.5 Contact Voice Telephone: (314)263-4486 or DSN693-4486
7.4.7 Contact Facsimile Telephone: (314)263-4102 or DSN693-4102
7.4.8 Contact Electronic Mail: wgs84@nga.mil
7.4.9 Hours of Service: 0900-1500 Mon to Fri (Central Time)
7.5 Metadata Standard Name: FGDC Content Standards for Digital Geospatial Metadata
7.6 Metadata Standard Version: June 8, 1994

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Point of Contact: Office of Geomatics
phone (314) 676-9127, DSN 846-9127
wgs84@nga.mil

Document last modified April 29, 2013