http://dug9.users.sourceforge.net/web3d/temp/geospatial_SRF_Convert_WalkSurface_Nav_Tile_Sys_rev2.html Comments welcome -Doug Sanden All new nodes are now at the bottom of the Node Reference section for easy finding 1) GeoSystemExplicit now covers all the factors in 2007 proposal. 2) Tiles > fields and naming closer to cesium tiles