Characteristics of the regional geoid model GGM-CA-2015
20/09/2016 | 17:45 | Session 3: Local/regional geoid determination methods and models
Author(s): David Avalos, Peter Vanicek, Marcelo Santos and Jianliang Huang
David Avalos, Peter Vanicek, Marcelo Santos and Jianliang Huang
The gravimetric geoid model for Mexico, Central America and the Caribbean, called GGM-CA-2015, is the first release from a working group of specialists representing 8 national cartographic institutions. It covers latitude north 6° to 33° and longitude west 58° to 119° with a resolution of 2.5’.
In preparation for the construction of the GGM-CA-2015 a free air gravity anomaly model was assembled using the most recently available datasets from the Dominican Republic, Panama, Costa Rica, Nicaragua, Honduras, El Salvador, Guatemala and Mexico. In order to increase the reliability of such information an effort was made in data cleaning. Geoidal heights were computed by the Stokes-Helmert technique using a reference spheroid complete to spherical harmonic degree and order 180 as derived from the satellite geopotential model GOC0-05s.
The geoidal heights are compared to GPS/leveling data as well as to EGM2008 geoid undulation resulting in differences in the order of a few decimeters in standard deviation. Larger differences appear in mountainous areas, reaching up to 2 m. The GGM-CA-2015 is recommended for test and assessment purposes in order to detect error sources and develop improvements.