pro draw_colorbar, x0,x1,y0,dy,bartlt,bartickv,bartickn,start=stc

  if not keyword_set(stc) then stc=0
  loadct,0
  for i=0,17-stc do begin
    ;print,(i+stc)*15
    polyfill, [x0,x0,x1,x1],[y0+i*dy,y0+(i+1)*dy,y0+(i+1)*dy,y0+i*dy],color=(i+stc)*15, /normal
  endfor

  topy=y0+(18.5-stc)*dy
  xyouts, x0-.02,topy,bartlt,charsize=.8,/normal

  ticn=n_elements(bartickv)

  for i=0, ticn-1 do begin
    xyouts, x1+.006,y0+(bartickv[i]/15.-stc)*dy,bartickn[i],charsize=.8,/normal
  endfor

end