A base class for custom globe overlay plugins. Your class must derive from the interface to add custom globe overlays.

GetURI	Gets the URI, if applicable.
OnInitialize	Called automatically when imagery is being added to the globe. Use the Context object to initialize the imagery extents, specify a Tiler object, projection, translucency, etc. The Scene is the scene the imagery is being added to.
OnUninitialize	Called automatically when imagery is being removed from the globe. The Scene is the scene the imagery is being removed from.
Read	Reads a tile for the specified extent and data. Set the raster through the context. Extent is the extent of the tile, Data is a user-specified data for the tile (valid only if Tiler was provided). Returns true if the operation was successful.