;+
  pro process_aster, itype, data=data, srs_smoothed=srs_smoothed

  dir      = './aster/'
  source   = 'ASTER Spectral Library'
  class    = 'Tap Water'
  format   = '(f6.3, 2x, 2f9.4)'

  ; specify the type
  itype = itype

  ; files for different type of surfaces
  ; 0. tap water
  ; 1. sea water
  ; 2. fine size snow
  ; 3. miedium size granular snow
  ; 4. deciduous tree
  ; 5. green grass
  ; 6. dry grass
  
  classes = [ 'tap water', $
              'sea water', $
              'fine size snow', $
              'miedium size granular snow', $  
              'deciduous tree', $
              'green grass', $
              'dry grass']

  asterfile = ['jhu.becknic.water.tap.none.liquid.tapwater.spectrum.txt', $
               'jhu.becknic.water.sea.none.liquid.seawater.spectrum.txt', $
               'jhu.becknic.water.snow.fine.24um.fine.spectrum.txt', $
               'jhu.becknic.water.snow.granular.82um.medium.spectrum.txt', $
               'jhu.becknic.vegetation.trees.deciduous.solid.decidou.spectrum.txt', $
               'jhu.becknic.vegetation.grass.green.solid.gras.spectrum.txt', $
               'jhu.becknic.vegetation.grass.dry.solid.drygras.spectrum.txt' ]
     
  outfiles  = ['tap_water.dat', $
               'sea_water.dat', $
               'fine_snow.dat', $
               'medium_snow.dat', $
               'deciduous_tree.dat', $
               'green_grass.dat', $
               'dry_grass.dat' ]

  nsmooth   = [ 21, 21, 5, 5, 5, 5, 21 ] ; number of points used for polynormial smoothness 

  read_aster_srs, dir+asterfile[itype], data

  srs_smoothed = poly_smooth(data.srs,nsmooth[itype])

  n = n_elements( data.lamda )
  
  openw, 11, outfiles[itype]
  
  printf, 11, 'Source: ', source
  printf, 11, 'Class: ', classes[itype]
  printf, 11, 'Colums: wavelength(um), smoothed spectra, original spectra'
  printf, 11, n, format='(i5)'
  for i = 0, n-1 do printf, 11, data.lamda[i], srs_smoothed[i], data.srs[i], format=format
  close, 11
  
  end