x = RANDOMN(seed, 50) ; Make 50 normal XY points. y = RANDOMN(seed, 50) z = EXP(-(x^2 + y^2)) ; Make the Gaussian. PLOT, x, y, psym=1 ; Show points. TRIANGULATE, x, y, tr, b ; Obtain triangulation. FOR i=0, N_ELEMENTS(tr)/3-1 DO BEGIN ; Show the triangles. t = [tr(*,i), tr(0,i)] ; Subscripts of vertices [0,1,2,0]. PLOTS, x(t), y(t) ; Connect triangles. ENDFOR k=GET_KBRD(1) SURFACE, TRIGRID(x, y, z, tr) ; Show linear surface. k=GET_KBRD(1) SURFACE, TRIGRID(x, y, z, tr, /QUINTIC) ; Show smooth quintic surface. k=GET_KBRD(1) SURFACE, TRIGRID(x, y, z, tr, EXTRA = b) ; Show smooth extrapolated surface. END