SURFACE

controls

  \NORMAL     -- a normal surface plot (default)
  \HISTOGRAM  -- a histogram surface
  \XZLINES    -- lines are drawn parallel to the x- and z-axes (default)
  \XLINES     -- lines are drawn parallel to the x-axis only
  \ZLINES     -- lines are drawn parallel to the z-axis only

  xangle      -- rotation angle about the x-axis (default = -45 degrees}
  zangle      -- rotation angle about the z-axis (default = -45 degrees)
  vsf         -- vertical scale value            (default = 1)
  psf         -- pedestal size scale value       (default = 0)

COLOUR

 If the \COLOUR qualifier is used, the height of the surface will be
 divided into 7 regions and a different colour associated with each region.
 This allows the user to quickly identify areas of similar height.