* Patch
A single patch that contains data at two resolutions.
** trile
Geode that contains a triangle tile of data
** strip
connecting geometry between triangles
* PatchGroup
A node in the LOD scheme. Contains a patch and the 4 children at the
next level of detail.
* GeoPatch
A patch that is part of the Euler projected cube scheme
** inherits from osg::MatrixTransform

