Surface ramp above mode
The surface_ramp_above_mode setting is for coloring molecular surfaces by electrostatic potential, using a color ramp. If on, the surface is colored by the potential on the solvent accessible surface, which is one solvent radius above the surface.
Coloring with surface_solvent=0 and surface_ramp_above_mode=0 is less meaningful, since a solvent or ligand atom never reaches the molecular surface of the protein (only the accessible surface). Furthermore, surface_solvent=1 with surface_ramp_above_mode=1 isn't meaningful either.
load molecule.pdb load electrostaticmap.dx ramp_new espramp, electrostaticmap, [ -3, 0, 3] show surface set surface_color, espramp set surface_ramp_above_mode