!------------------------------------------------------------------------ 
! OVRO.GRAPHIC
! Procedure to define contour levels for multichannel image 
! Variables defined in DEFINE.GRAPHIC 
! S.Guilloteau 1-Apr-1999
!------------------------------------------------------------------------ 
define real range expo mant rms 
define integer n1 n2 
! 
if (&1%extrema.eq.0) then       ! means no extrema section 
  compute &1%min min &1 
  compute &1%max max &1 
  let &1%extrema 2 
endif 
compute rms rms &1
let true_spacing = rms
!
let n1 nint(&1%min|true_spacing) 
let n2 nint(&1%max|true_spacing) 
if (n1.lt.0.and.n2.gt.0) then 
  levels true_spacing*n1 to -1.95*true_spacing by true_spacing 2*true_spacing to true_spacing*(n2+0.05) by true_spacing 
else if (n1.gt.0) then 
  let n1 max(n1,2) 
  levels true_spacing*n1 to true_spacing*(n2+0.05) by true_spacing 
else 
  let n1 -max(-n1,2) 
  levels true_spacing*n1 to true_spacing*(n2+0.05) by true_spacing 
endif 
let level_min true_spacing*n1 
let level_max true_spacing*n2