Mexico North-South Deflections (DMEX97)

Metadata Updated: November 12, 2020

This 2' surface deflection of the vertical grid for Mexico, and North-Central is the DMEX97 model. The computation used about one million terrestrial and marine gravity measurements heldin the NGS database as of March 1997. These gravity measurements were augmented by data contributions from NGA (former National Imagery and Mapping Agency), and satellitealtimeter derived gravity anomalies computed by Sandwell and Smith (1997). The deflection values themselves were obtained by numerical differentiation of cubic spline models along the meridians of the MEXICO97 geoid grid, followed by a correction for curvature of the plumb line, yielding surface deflections of the vertical. Since the EGM96 model was used to fill data gaps south of 20 degrees North latitude, the deflections in and around those regions will be less accurate. The gravity values are based on the International Gravity Standardization Net 1971 (IGSN71). The deflections are referred to Geodetic Reference System 1980 (GRS80) ellipsoidal normals oriented in the International Terrestrial Reference Frame 1994 (ITRF94(1996.0)). We are particularly grateful to NGA (former National Imagery and Mapping Agency) for their assistance and their data contributions.

Access & Use Information

License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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Dates

Metadata Date September 25, 2017
Metadata Created Date November 12, 2020
Metadata Updated Date November 12, 2020
Reference Date(s) January 1, 1999 (publication)
Frequency Of Update irregular

Metadata Source

Harvested from NGDC MGG Geophysics

Additional Metadata

Resource Type Dataset
Metadata Date September 25, 2017
Metadata Created Date November 12, 2020
Metadata Updated Date November 12, 2020
Reference Date(s) January 1, 1999 (publication)
Responsible Party NOAA National Centers for Environmental Information (Point of Contact)
Contact Email
Guid gov.noaa.ngdc.mgg.geophysics:G01432
Access Constraints Distribution liability: NOAA and NCEI make no warranty, expressed or implied, regarding these data, nor does the fact of distribution constitute such a warranty. NOAA and NCEI cannot assume liability for any damages caused by any errors or omissions in these data. If appropriate, NCEI can only certify that the data it distributes are an authentic copy of the records that were accepted for inclusion in the NCEI archives., Use Constraints: If you use this data, please cite the National Geophysical Data Center and the originator of the data., Access Constraints: None
Bbox East Long -75
Bbox North Lat 33
Bbox South Lat 14
Bbox West Long -119
Coupled Resource
Frequency Of Update irregular
Licence
Metadata Language eng; USA
Metadata Type geospatial
Progress completed
Spatial Data Service Type
Spatial Reference System urn:ogc:def:crs:EPSG::5715
Spatial Harvester True

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