each chunk is composed 3 elements:

1) Raster data      Textures Colors, Specular, NormalMaps, NightLights ...
2) Vectorial data   VectInfoCollection -> VectInfo -> VectObject ....
3) Geometry data    FLAT / HeightField / 3D Object...

chunks are composing a quadtree

6 quadtree constitute a full planet ( 6 faces of the cube ) 
