ElevationGrid nodes provide a simple way to construct terrain-like geometry.
Building terrain sets is very common: hills, valleys, mountains and other tricky uses.
An ElevationGrid geometry node creates terrains using xDimension and zDimension for grid size, with
xSpacing and zSpacing for row and column distances, and then includes
height elevations at each of the grid points.
These X3D scenes are adapted directly from the
original VRML 2.0 Sourcebook chapter examples.
Introduction to VRML97 SIGGRAPH98 course notes.