;------------------------------------------------------------
;------------------------------------------------------------
;------------------------------------------------------------
;+
;
; @file_comments write the bathymetry ASCII file of OPA
;
; @categories for OPA
;
; @param zbat {in}{required} the bathymetry, a 2d array  
; @param filename {in}{required} a string containing the filename,  
;
; @history Sebastien Masson (smasson\@lodyc.jussieu.fr)
;                      Sept 30, 2003
;    based on batsav2.pro, written by Maurice Imbard, March 17, 1998
;-
PRO writebat, zbat, filename
; basic checks
  IF n_params() NE 2 THEN BEGIN
    print, 'bad number of aguments in the call of writebat'
    return
  ENDIF
  IF size(filename, /type) NE 7 THEN BEGIN
    print, 'the filename should be a string'
    return
  ENDIF
  sbat = size(zbat)
  IF sbat[0] NE 2 THEN BEGIN
    print, 'bathymetry array should be 2d array'
    return
  ENDIF
;
  jpi2 = sbat[1]
  jpj2 = sbat[2]
; parameters def
  ifreq  = 40
  ifin   = jpi2/ifreq+1
  irest  = jpi2-(ifin-1)*ifreq
  zbati  = intarr(ifreq)
  zbati2 = intarr(irest)
  i0     = intarr(ifreq/5)
  i1     = intarr(max([1, irest/5]))
;
  openw, iunit, filename, /get_lun
;;
;; fill the file
;;
  printf, iunit, FORMAT = '(1x," bathy IDL     ",2i8)', jpi2, jpj2
  printf, iunit, FORMAT = '(/)'
  il1 = 0
  FOR jn = 1, ifin-1 DO BEGIN
    printf, iunit, FORMAT = '(/)'
    il2 = min([ jpi2-1, il1+ifreq-1] )
    i0[0] = il1+1
    FOR jj = 1, ifreq/5-1 DO BEGIN
      i0[jj] = i0[jj-1]+5
    END
    printf, iunit, FORMAT = '(3x,13(i3,12x))', i0
    printf, iunit, FORMAT = '(/)'
    il3 = il2-(jn-1)*ifreq
    iformat = string('(', il3+2, 'i3)')
    FOR jj =  jpj2-1, 0, -1  DO BEGIN
      zbati(0:il3) = zbat(il1:il2, jj)
      printf, iunit, FORMAT = iformat, jj+1, zbati
    END
    il1 = il1 + ifreq
  END
  printf, iunit, FORMAT = '(/)'
  il2 = min([ jpi2-1, il1+ifreq-1] )
  i1[0] = il1+1
  FOR jj = 1, irest/5-1 DO BEGIN
    i1[jj] = i1[jj-1]+5
  END
  printf, iunit, FORMAT = '(3x,13(i3,12x))', i1
  printf, iunit, FORMAT = '(/)'
  il3 = il2-(ifin-1)*ifreq
  iformat = string('(', il3+2, 'i3)')
  FOR jj =  jpj2-1, 0, -1  DO BEGIN
    zbati2(0:irest-1) = 0
    zbati2(0:il3) = zbat(il1:il2, jj)
    printf, iunit, FORMAT = iformat, jj+1, zbati2
  END
;;
;; end
;;
  close, iunit
  free_lun, iunit
;
  return
end