Start:

 - Create a "New IDL Source file" ... under "FILE" tape or click icon.

Step (1)  Enter, Save, Compile and Run the following short program.

PRO myprog
 
  file=dialog_pickfile() 
  print,file
  
  status = MTK_FILE_TO_PATH( file, path )
  print, 'Path = ', path

end


Step 2)   Add lines to load NIR radiance data from block 93 and display it

  block=93
  grid='NIRBand'
  field='NIR Radiance/RDQI'
  status = MTK_READBLOCK(file, grid, field, block, data)
  print, 'Status =', status
  iimage, data 


Step 3)    Now look at MISR Radiometric Cloud Mask (the RCCM) for the nadir camera

  ; replace "grid" and "field" values above with the following  (See DPS Table 6-40)
  grid='RCCM'
  field='Cloud'


Step 4)    After running replace "pickfile" with fixed file name ... 

   file = ' ... '
  

Step 5)  Determine Latitude and Longitude point in MISR Cloud Mask (the RCCM) 

  ; define resolution of RCCM field and the "x,y" point for which we want to find the lat lon
  res   = 1100
  samp  = 1024
  line  = 500

  status = MTK_BLS_TO_LATLON( path, res, block, line, samp, lat, lon )
  print, lat
  print, lon


Step 6)  Now lets extract data with 100 km of this point

  extent=100
  units='km'
  status = MTK_SETREGION_BY_LATLON_EXTENT( lat, lon, extent, extent, units, region )
  print, region   

  status      = MTK_READDATA( file, grid, field, region, data, map )

  ; NOTE RCCM mask has values from 1 to 4.   A value of 1 means cloud with High Confidence
  ; data_HC = data eq 1
  ; iimage, data_HC

  
Step 7)  Now lets calculate cloud fraction ... add to the end of the program ...

  cpts = total(dataC)
  print, 'cloudy points = ',cpts
  
  pts = size(dataC)
  print,' total points = ',pts(4)
  
  CF=cpts/pts(4)
  print, 'cloud fraction = ',CF
  

Step 8)  Now lets calculate cloud fraction for each MISR angle.

  ; at top of the program add ..
  Camera=['DF', 'CF', 'BF', 'AF', 'AN', 'AA', 'BA', 'CA', 'DA']
  Angle=[70.5, 60, 45, 26, 0, -26, -45, -60, -70.5]
  CF=fltarr(9)
  for loop=0,8 do begin
  print, Camera(loop)

  ; then below the  file='...'  command
  pos = strpos(file,'AN')
  file = strmid(file,0,pos)+Camera(loop)+strmid(file,pos+2) 
  print,file

  ; at the bottom add
  CF(loop)=cpts/pts(4)
  print, 'cloud fraction = ',CF(loop)
  endfor
  plot,Angle,CF