IDL读取MODIS 1B数据中250分辨率下的数据

Varname=EV_250_RefSB
file=dialog_pickfile(default_extension='.hdf',filter='*.hdf'
hdfid=hdf_sd_start(file)
index=hdf_sd_nametoindex(hdfid,varname)
varid=hdf_sd_select(hdfid,index)
hdf_sd_getdata,varid,data,_extra=extra_kewords
hdf_sd_endaccess,varid