dem_scr.pro

;DEM积雪覆盖率
;author：shaodonghang
pro DEM_SCR
  ;打开数据
  COMPILE_OPT IDL2
  ENVI, /RESTORE_BASE_SAVE_FILES
  ENVI_BATCH_INIT, LOG_FILE='BATCH.LOG'
  print,'Start time: ',systime()
  begintime = systime(1)
  
  ROOT_DIR = 'H:\2000-2001逐月积雪面积数据\2011\DEM5\'
  FNS = FILE_SEARCH(ROOT_DIR,'*.tif',COUNT = COUNT)
  PRINT, 'There ara totally', COUNT,' images.'
  for i=0,COUNT-1 do begin
  fn = FNS[i]
  envi_open_file, fn, r_fid=fid
  envi_file_query, fid, ns=ns, nl=nl, nb=nb, dims=dims, $
    data_type=data_type, interleave=interleave, offset=offset
  map_info=envi_get_map_info(fid=fid)
  ;读取波段
  band=envi_get_data(fid=fid, dims=dims, pos=0)
  a=total(double(band))   ;计算波段的总和
  b=3415680               ;减去空白部分的无效值DEM1=3374720,DEM2=3143296,DEM3=2749184,DEM4=2958080,DEM5=3415680
  s=a-b                   ;像元总数
  d=30                    ;DEM1=350,DEM2=2158,DEM3=5237,DEM4=3605,DEM5=30
  R=double(s/d)           ;积雪覆盖率
  print, R,format='(i3)'  ;最终结果,精确到小数点后4位
  endfor 
  
  print,'End time: ',systime()
  endtime = systime(1)
  timespan = endtime-begintime
  print,'Run Time: '+string(timespan)+' s'
  envi_batch_exit
end