Office of Geomatics

Enabling GEOINT accuracy through geodetic, geophysical and photogrammetric sciences and content.

"Geodesy remains our life blood"

-- Robert Cardillo, NGA Director
The Director's Intent, 10/3/14
Products and/or services described may only be available to authorized customers.

World Geodetic System 1984 (WGS 84)

The World Geodetic System 1984 (WGS 84) is a 3-dimensional coordinate reference frame for establishing latitude, longitude and heights for navigation, positioning and targeting for the DoD, IC, NATO, International Hydrographic Office and the International Civil Aviation Organization. WGS 84 represents the best global geodetic reference system for the Earth available at this time for practical applications of mapping, charting, geopositioning, and navigation. This standard includes the definition of the coordinate systems fundamental and derived constants, the ellipsoidal (normal) Earth Gravitational Model (EGM), a description of the associated World Magnetic Model (WMM), and a current list of local datum transformations. NGA and the National System for Geospatial-Intelligence (NSG) recommends clicking the following link for further specifications on WGS 84 DoD IT Standards Registry (DISR) (PKI Certs required).


Earth Gravitational Model (EGM)

This division in the Office of Geomatics at NGA is responsible for collecting, processing, and evaluating gravity data (free-air and Bouguer gravity anomalies). These data are then used to compute gravimetric quantities such as mean gravity anomalies, geoid heights, deflections of the vertical, and gravity disturbances. All of these quantities are used in World Geodetic System 1984 support, navigation systems, mapping projects, and different types of surveys.

An Earth Gravitational Model (EGM) is set of geopotential coefficients used in a spherical harmonic expansion to create a global potential surface to coincide with Mean Sea Level (MSL). This surface is called a geoid and it fluctuates above and below the reference ellipsoid surface established by WGS 84. For more information, click on a drop-down menu item above on the EGM tab.

Earth Gravitational Model 2008 (EGM2008)

The EGM84 and EGM96 are legacy products. Users are recommend to use the latest EGM from NGA, currently EGM2008. In 2020, NGA plans to release a new EGM, tentatively named EGM2020, where upon EGM2008 will become a legacy product.

The EGM2008 is provided as a set of normalized, geopotential coefficients complete to degree and order 2159, and contains additional spherical harmonic coefficients extending to degree 2190 and order 2159. Also provided is a 2.5-minute worldwide geoid height file, precomputed from the EGM2008. The coefficient and geoid height files have associated software and documents. EGM2008 was approved for official DoD use as documented in NGA STND.0036_1.0, 2014-07-08.


WHAT'S NEW

April, 2013 - EGM2008 Citation included below with Links to reference EGM2008 and the EGM2008 Erratum are given on left under Additional Information.

EGM2008 Citation: The development and evaluation of the Earth Gravitational Model 2008 (EGM2008) - Nikolaos K. Pavlis, Simon A. Holmes, Steve C. Kenyon, John K. Factor; Journal of Geophysical Research: Solid Earth (1978-2012) Volume 117, Issue B4, April 2012.

May, 2009 - Global 2.5 Minute Geoid Undulation Grid available in GIS format.
February, 2009 - Middle East Geoid Undulation Grid available in GIS format.
February, 2009 - Propagated Error Estimates of EGM2008 released.
January, 2009 - Utility to convert binary files from Big Endian to Small Endian released.
January, 2009 - Gravity Anomalies & Deflections of the Vertical data released.
November, 2008 - SMALL ENDIAN versions of binary files released.
November, 2008 - Files & Products for Oceanographic Applications released.
July, 2008 - WGS 84 version of EGM2008 released. Includes grids and programs for computing geoid undulations relative to WGS 84 Ellipsoid.

Please provide comments, suggestions, and feedback to NGA Public Affairs Office (bottom right of page).

Earth Gravitational Model 1996 (EGM96)

The EGM84 and EGM96 are legacy products. Users are recommend to use the latest EGM from NGA, currently EGM2008. In 2020, NGA plans to release a new EGM, tentatively named EGM2020, where upon EGM2008 will become a legacy product.

The EGM96 is provided as a set of normalized, geopotential coefficients to degree and order 360. Also provided is a 15-minute worldwide geoid height file, precomputed from the EGM96. The coefficient and geoid height files have associated software and documents. EGM96 was approved for official DoD use as documented in NIMA TR8350.2, Third Edition, 4 July 1997.

Earth Gravitational Model 1984 (EGM84)

The EGM84 and EGM96 are legacy products. Users are recommend to use the latest EGM from NGA, currently EGM2008. In 2020, NGA plans to release a new EGM, tentatively named EGM2020, where upon EGM2008 will become a legacy product.

The EGM84 is provided as a set of normalized, geopotential coefficients to degree and order 180. Also provided is a 30-minute worldwide geoid height file, precomputed from the EGM84. The coefficient and geoid height files have associated software and documents. EGM84 was approved for official DoD use as documented in DMA TR8350.2, Second Edition, 1 September 1991.

World Magnetic Model (WMM)

The World Magnetic Model is the standard model used by the U.S. Department of Defense (DoD), the U.K. Ministry of Defence, the North Atlantic Treaty Organization (NATO) and the International Hydrographic Organization (IHO), for navigation, attitude and heading referencing systems using the geomagnetic field. It is also used widely in civilian navigation and heading systems. The model, associated software, and documentation are distributed by the National Oceanic and Atmospheric Administration (NOAA), National Centers for Environmental Information (NCEI) on behalf of NGA. The model is produced at 5-year intervals. With the current model expiring on December 31, 2019.

Datum Transformations & Conversions

Data acquired by NGA and referenced to a geodetic datum other than WGS 84 does not meet agency standards, and must therefore undergo a datum transformation to WGS 84. For assistance setting up geographic translations, acquiring grid system and datum parameters, running batch conversions, and loading MSP Geotrans please refer to the GEOTRANS menu item on the Data/Apps tab.

Definitions

A transformation, or more specifically a geodetic datum transformation, is a change in a coordinate based on to what geodetic datum a coordinate is referenced. The NGA and DoD approved geographic translator to perform geodetic datum transformations is MSP GEOTRANS.

A conversion, or more specifically a coordinate conversion, is a change in coordinate data from one reference system to another. The NGA and DoD approved geographic translator to perform coordinate conversions is MSP GEOTRANS.

MSP (Mensuration Services Program) GEOTRANS (Geographic Translator) v.3.8

MSP GEOTRANS is the NGA and DOD approved coordinate converter and datum translator. The user-friendly GUI has features including batch conversion capability, a choice of precision levels and the capability to add your own datum. MSP GEOTRANS can be downloaded to run as a stand-alone application. Available downloads are listed below.

Operating Systems and Compilers Supported:
  • Windows 7, 64-bit, Visual Studio 2015
  • Windows 10, 32-bit, Visual Studio 2015
  • Windows 10, 64-bit, Visual Studio 2015
  • RHEL 7, 64-bit, GCC 4.8.5

NOTE: GeoTrans 3.8 retired support for all Windows versions using the Visual Studio 2010, 2012, and 2013 compilers, and RedHat Linux 6.

New Coordinate Systems Supported:
  • Equatorial Spherical as defined by ISO/IEC 18026 Table 5.10 (GeoTrans labels this coordinate system Geocentric Spherical)
  • Lococentric Azimuthal Spherical as defined by ISO/IEC 18026 Table 5.13 (GeoTrans labels this coordinate system Local Spherical)
Bug Fixes:
  • Fixed UTM to MGRS conversion bug that caused an intermediate coordinate conversion to be performed
  • Corrected UTM to MGRS conversion to apply the datum shift
  • Fixed memory leaks in datumLibraryImplementation.cpp
  • Modified GUI to specify that the US Survey Foot was the English unit of measure for geodetic height values
  • Fixed the truncation of MGRS coordinates by adding one-half the precision in MGRS to UTM conversions
  • Fixed the header file in LambertConformalConic1.h
  • Fixed problem preventing the installation of GeoTrans on Windows 10 computers
  • Fixed bug in the conversion from geocentric to geodetic coordinates in the special case of z = 0

MSP GEOTRANS Documents
MSP GEOTRANS Downloads

GeoTrans 3.8 requires Java Runtime Environment (JRE) 1.8 or later to execute (JRE 1.8.0.192 or later is recommended). Refer to the MSP GeoTrans 3.8 Release Notes for information on how to check your Java version and download JRE 1.8.0.192.

There are four versions of GeoTrans available for download, one intended for end users and three for software developers. After downloading the appropriate version please refer to the MSP GeoTrans 3.8 Release Notes for proper installation instructions and for detailed descriptions of the changes included in this release.

End User Version:

The End User version is recommended for the majority of the GeoTrans users and contains everything necessary to run GeoTrans, to include the GeoTrans on-line help. Windows users should determine whether the 32- or 64-bit version is appropriate for their installation based on whether they have a 32- or 64-bit version of Java installed.

Developer Version:

The Developer version is for software developers and contains the GeoTrans executable software plus the GeoTrans source code, documentation and a programmer's guide.

  • Windows Developer - SHA256: 54EDB287FAB8AE5C4743F3CBEB1CF41A60DE5FEE1AF6E0DCF91B9283928DC018
  • Linux Developer - SHA256: 94B9038ACFEECC869CEF635CC475E531AAE1BBA569F3A395B08A6219F5D4A057
MGRS Version:

The MGRS version is for software developers who only need the MGRS, UTM, UPS, Transverse Mercator and Polar Stereographic modules, source code and documentation. It does not include any GeoTrans executable software.

  • MGRS Windows - SHA256: 8721A45B836DF20B445B9BC0ADD648FD0D57308468CD5058B7C46A9E57A8EA94
  • MGRS Linux - SHA256: EAE6B2DBBD0B7B17C15AF1E8DD1B4BA8D03256D028C71A42AB90F4D9CBCBCA9A
Master Version:

The Master version is for software developers and includes all of the GeoTrans executables for all platforms, all source code and all documentation. The only difference between the Windows and Linux version is the method used to zip the files.

  • Windows Master - SHA256: 54EDB287FAB8AE5C4743F3CBEB1CF41A60DE5FEE1AF6E0DCF91B9283928DC018
  • Linux Master - SHA256: BAA72D3B1AE12F237A8AD30F2DEB3FED2B80FEB759528EA0A72B4B42CB77C565

MSP GEOTRANS Assistance

Having trouble starting GEOTRANS? Here are some suggestions
If you have installed GEOTRANS and are unable to get it to start (no message given) you may need to download the MS Visual C++ Redistributable Package. This software is normally included on a computer, but system configurations do vary. Please read the instructions for installing GEOTRANS on a Network Drive.

MS Visual C++ Redistributable Package for 32-bit user download: http://www.microsoft.com/en-us/download/details.aspx?id=5582

MS Visual C++ Redistributable Package for 64-bit user download: http://www.microsoft.com/en-us/download/details.aspx?id=14632

NOTE: Java 32-bit and 64-bit may be required to run MSP GEOTRANS. GEOTRANS 3.8 was built using Java JDK 1.8 update 192. The latest releases of Java can be found at Orcale.com. Should you encounter a Windows Error 2 condition during MSP GEOTRANS install, this error usually occurs because the wrong bit-level for Java was selected. Especially with Java 1.8, the Windows environment variable for PATH is often not set correctly. You may try the following procedure to correct the condition:

  1. Right click on Computer and select properties.
  2. On the left panel, click on Advanced system settings.
  3. At the bottom of the Advanced tab, click on Environment Variables...
  4. Under the System variables, select Path and click Edit.
  5. Change the Variable values for C:\ProgramData\Oracle\Java\javapath to C:\Program Files (x86)\Java\<your java version>\bin
  6. Click Ok and exit out of the Advanced tab


Contact the MSP/GEOTRANS Help Desk
For assistance with MSP GEOTRANS software, including questions about source code, please email MSP_Help@nga.mil (Unclassified content only).

Earth Gravitational Model 2008 (EGM2008) Data and Apps

The following links contain documentation, source code, data, and supporting inputs and tools for EGM2008.

FILE/LINK DESCRIPTION
EGM2008 Spherical Harmonics (104MB)
Zip archive containing all EGM2008 Spherical Harmonics code and documentation.
EGM2008 2.5 Minute Interpolation Grid (128MB)
Zip archive containing all EGM2008 2.5 Minute Interpolation Grid code and documentation.
Earth Gravitational Model 96 (EGM96) Data and Apps

The following links contain documentation, source code, data, and supporting inputs and tools for EGM96.

FILE/LINK DESCRIPTION
360 Spherical Harmonics
Zip archive containing all EGM96 360 Spherical Harmonics code and documentation.
15 Minute Interpolation Grid
Zip archive containing all EGM96 15 Minute Interpolation Grid code and documentation.
EGM96 Geoid Calculator
Online calculator to determine EGM84 geoid height based on latitude and longitude inputs.
Earth Gravitational Model 1984 (EGM84) Data and Apps

The following links contain documentation, source code, data, and supporting inputs and tools for EGM84.

FILE/LINK DESCRIPTION
180 Spherical Harmonics
Zip archive containing all EGM84 Spherical Harmonics code and documentation.
30 Minute Interpolation Grid
Zip archive containing all EGM84 30 Minute Interpolation Grid code and documentation.
EGM84 Geoid Calculator
Online calculator to determine EGM84 geoid height based on latitude and longitude inputs.
World Magnetic Model (WMM) 2015 - Apps

World Magnetic Model 2015 - Data

WMM 2015 has been replaced by WMM 2015v2 below.


World Magnetic Model 2015 Update (WMM 2015v2) - Data

An update to the World Magnetic Model (WMM) 2015 was released October 2018 and can be downloaded below. The file contains the necessary coefficients to upload into systems that require the update. A full report with more information about the WMM and this update will be published by NOAA's National Center for Environmental Information on their website when the partial government shutdown is over. This update will not impact the release of WMM 2020.

The WMM is the standard model used by DoD, NATO, and IHO for a wide range of positional and navigation systems. Feedback from the WMM user community as well as the degree of the variation in the northern hemisphere drove the decision to make this out-of-cycle update. The model seeks to mitigate any user performance degradation caused by a one-degree gridded variation (GV) in the polar region. An increased GV error may adversely affect compass navigation and other magnetic field-based systems in the arctic region.

Download WMM 2015 Update (October 2018).

Services

Services require PKI certs and allow visualization via the IC Portal or ArcGIS desktop (download). After selecting the link below, additional viewing options may be available by following the link under the "Map Contents" heading.

SERVICE NAME LINK DESCRIPTION
Earth Gravity Model 2008 (EGM08)
MoW
REST Endpoint
EGM08 is an interpreted grid of the spherical harmonics model of the earth's gravitational potential. The grid was formed by merging terrestrial, alimetry-derived and airborne gravity data. EGM08 is complete to degree and order 2159, and contains additional coefficients up to degree 2190 and order 2159.
World Magnetic Model 2015 (WMM)
MoW
REST Endpoint
The World Magnetic Model (WMM) is a set of data, software and charts used to characterize, depict, and predict various properties of the earth's magnetic field. Primarily used for portraying declination data (magnetic north) on maps and charts. The model is produced at 5-year intervals, with the current model expiring 31 Dec 2019.
WGS 84 Resources & Links

DOCUMENT DESCRIPTION DOCUMENT
NGA.STND.0036_1.0.0_WGS84
NGA Standardization Document, Department of Defense, World Geodetic System 1984 (updated 8 July 2014) WGS 84 definition and relationships with local geodetic systems.


POINT OF CONTACT
NGA Public Affairs
publicaffairs@nga.mil
Phone: 571-557-5400
Last modified: 19-Nov-19