Earth

National Oceanic and Atmospheric Administration

 National Geodetic Survey

The Earth is an irregular surface and is difficult to model

http://www.ngs.noaa.gov/INFO/WhatWeDo.shtml

h-Geometry Model of the Earth

http://adsabs.harvard.edu/abs/2010GeCar..36..160Z

h-Geometry Model of the Earth

2016.01.07