【20090717-01】ArcGlobe
http://edndoc.esri.com/arcobjects/9.2/CPP_VB6_VBA_VCPP_Doc/COM/VCpp/lib_overviews/globecore_overview.htm
The Globe object is one of the main objects of the library since it is the container for data layers, similar to the Map object.
The GlobeDisplay object, analogous to the SceneGraph coclass of 3DAnalyst Library, is a container for data caching and for events that occur in the globe. These events include those that occur when there is a change in the active view to events that trigger to notify data caching state. The GlobeDisplay object has a central role in that it also manages, specifies and controls different optimization schemes of the application.
the GlobeCamera object that specifies the perspective of a 3D globe display rendering, to define the positioning of the globe relative to the observer. In ArcGlobe the 3D display window is represented by the GlobeViewer object. It is similar in its function and properties to the SceneViewer object in 3DAnalyst library. The 3DAnalyst Library overview includes discussions about the GlobeViewer, SceneViewer and 3DViewer - a class that has common properties and methods of the two viewers. The Globe can have one or more layers, these layers specify the data on the Globe and how the data is drawn.
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Geocentric Coordinate System
Description
The geocentric coordinate system is not a planar coordinate system based on a map projection . It is a geographic coordinate system in which the earth is modeled as a sphere or spheroid in a right-handed X,Y,Z system measured from the center of the earth.
The X-axis points to the prime meridian, the Y-axis points 90° away in the equatorial plane, and the Z-axis points in the direction of the North Pole. 
A geocentric coordinate system is similar to a geographic coordinate system based on latitude and longitude, which measures angles from the earth's center.
Uses and applications
The geocentric coordinate system is used internally as a transient system. It is used as a framework for calculations as part of several geographic (datum) transformation methods.
Learn more about geographic transformation methods
