using GMT
Dsw = coast(dump=true, DCW=(country=:CH, file=:ODS)); # Get the Swiss border
FV = extrude(Dsw, 0.2)
viz(FV, zsize=1)
Create an extruded 2D/3D shape.
shape: The shape to extrude. It can be a 2D polygon or a 3D polygon defined by a Mx2 or Mx3 matrix or a GMTdataset
h: The height of the extrusion. Same units as in shape.
base: The base height of the 2D shape to extrude. Default is 0. Ignored if the shape is a 3D polygon.
closed: If true (the default), close the shape at top and bottom.
A GMTfv FacesVertices object.
Extrude the Swisserland.

And a much nicer example combining extrusion and painting top surface with flatfv.