I know when rendering terrain, terrain is usually equal-sized tiled, and a vbo with the same size is prepared. the tiles contain height values only. at runtime, this vbo is rendered and a vertex shader is used to do vertex texture fetch from such as tile A, and tile A is rendered. and then B C D...
but when it comes to real geographic data, it is not the case any more. because the earth on which we stand is an ellipsoid. terrain data are given as elevation from the ellipsoid, such as the SRTM data . tile A and tile B at ellipsoid do not have the same shape any more, and naturally a vbo can represent all tiles do not exist. the scheme using VTF does not work now.
so what is the solution in real GIS system? make the tiles contain all the 3 coordinates but not only the hight value?
thanks in advance!