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Mexico Geoid Heights (MEXICO97)

This 2' geoid height grid for Mexico, and North-Central America, is the MEXICO97 geoid model. The computation used about one million terrestrial and marine gravity measurements held in the NGS database as of March 1997. These gravity measurements were augmented by data contributions from NGA (former National Imagery and Mapping Agency), and satellite altimeter-derived gravity anomalies computed by Sandwell and Smith (1997). Large data gaps south of 20 degrees North latitude were filled with 15'x15' gravity values derived from the EGM96 global geopotential model. This helped control interpolation errors across the data gaps during the gridding of terrain corrected Bouguer anomalies. After gridding of the Bouguer anomalies, the Bouguer plate was restored, a degree 360 model of gravity anomalies (from EGM96) was removed, and the residual free-air anomalies in the data gaps (south of 20 degrees North Latitude) were zeroed. (This zeroing was found to be the best way currently available to yield a reasonable geoid in the data gaps). The residual Faye anomalies were converted to residual co-geoid undulations through a 1-D FFT formulation of Stokes' integral, and finally the EGM96 undulation model was restored, and the indirect effect applied. This means that in the data gaps, long wavelength information is provided by EGM96, short wavelength information is provided by the 2'x2' DTED (during the application of the indirect effect), but medium wavelength information (usually provided by gravity measurements) is missing altogether. Although the exact accuracy of the geoid in the data gaps is difficult to ascertain, the quoted accuracy for EGM96 (which is the primary source of geoid information in the data gaps) is below 50 cm in these areas. The gravity values are based on the International Gravity Standardization Net 1971 (IGSN71). The geoid heights are referred to the Geodetic Reference System 1980 (GRS80) ellipsoid, centered at the origin of the International Terrestrial Reference Frame 1994 (ITRF94(1996.0)). Additional information is available at: http://www.ngs.noaa.gov/GEOID/MEXICO97/ We are particularly grateful to NGA (former National Imagery and Mapping Agency) for their assistance and their data contributions.

Use Constraints: If you use this data, please cite the National Geophysical Data Center and the originator of the data.

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    Distribution Formats
    • Binary
    Distributor DOC/NOAA/NESDIS/NGDC - National Geophysical Data Center
    Point of Contact Susan McLean
    DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
    (303) 497-6478
    Susan.McLean@noaa.gov
    Documentation links not available.
    Originator
    • DOC/NOAA/NESDIS/NGDC - National Geophysical Data Center
    Publisher
    • DOC/NOAA/NESDIS/NGDC - National Geophysical Data Center
    Date(s)
    • publication: 1999-01-01
    Edition: 1999 Edition
    Dataset Progress Status Complete
    Data Update Frequency: Irregular
    Purpose: To provide easy access to global and regional gravity data and related models for scientific studies.
    Time Period:  to 
    Spatial Reference System: urn:ogc:def:crs:EPSG::5715
    Spatial Bounding Box Coordinates:
    N: 33
    S: 14
    E: -75
    W: -119
    Spatial Coverage Map:
    Themes
    • EARTH SCIENCE>SOLID EARTH>Geodetics/Gravity>Control Surveys
    • EARTH SCIENCE>SOLID EARTH>Geodetics/Gravity>Gravitational Field
    • EARTH SCIENCE>SOLID EARTH>Geodetics/Gravity>Gravity
    • EARTH SCIENCE>SOLID EARTH>Geodetics/Gravity>Reference Systems
    • EARTH SCIENCE>SOLID EARTH>Geodetics/Gravity>Satellite Orbits
    • Absolute Gravity
    • Bouguer Gravity
    • Free Air Anomaly
    • Gridded Gravity
    • Land Gravity
    • Observed Gravity
    • WDC/SEG, BOULDER>World Data Center for Solid Earth Geophysics, Boulder
    • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
    Places
    • Continent>North America>Mexico
    Use Constraints
    • Use Constraints: If you use this data, please cite the National Geophysical Data Center and the originator of the data.
    Access Constraints
    • Access Constraints: None
    Fees
    • Depends on the data set
    Source Datasets
    • Mexico Geoid Heights (MEXICO97)
      • Description of Source: Source Contribution: Gravity survey data Source Type: varies
      • Temporal extent used:   to 
    Lineage Statement Lineage statement not available.
    Processor
    • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
    Processing Steps
    • All data were processed by the source before being forwarded to the National Geophysical Data Center

    Metadata Last Modified: 2014-08-08

    For questions about the information on this page, please email: Brian.Meyer@noaa.gov