Re: calipso datasets

From: Dennis Shea <shea_at_nyahnyahspammersnyahnyah>
Date: Wed, 16 Apr 2008 10:18:24 -0600

Lin Su wrote:
> Dear All,
>
> Does anyone have any experience to work on the calipso satellite data using NCL? I found the software NASA provided is for idl users.
>
Hiu Lin,

It is a standard HDF file. You can always look at *any* supported
NCL file [nc, hdf, hdf-eos, grib-1, grib-2] by using ncl_filedump:

                      
http://www.ncl.ucar.edu/Document/Tools/ncl_filedump.shtml

%> ncl_filedump
CAL_LID_L2_40kmAProCal-Beta-V2-01.2007-04-03T05-00-44ZD.hdf | less

filename: CAL_LID_L2_40kmAProCal-Beta-V2-01.2007-04-03T05-00-44ZD
path: CAL_LID_L2_40kmAProCal-Beta-V2-01.2007-04-03T05-00-44ZD.hdf
   file global attributes:
      coremetadata :
GROUP = INVENTORYMETADATA
  GROUPTYPE = MASTERGROUP
  GROUP = GRANULE
    OBJECT = GRANULEID
      NUM_VAL = 1
      VALUE = "L2_LIDAR"
    END_OBJECT = GRANULEID
[SNIP ---------------------------------------------------------]

There are a number of "fakeDim*" Why? the HDF creators did not
name the dimensions!! Always explore the data .... this is how to
learn about it.
IMHO .... much simpler than IDL.

ncl 0> f = addfile
("CAL_LID_L2_40kmAProCal-Beta-V2-01.2007-04-03T05-00-44ZD.hdf" , "r")
ncl 1> print(f)
ncl 2> lstrt = f->Latitude_Start
ncl 3> print(lstrt)
Variable: lstrt
Type: float
Total Size: 4 bytes
            1 values
Number of Dimensions: 2
Dimensions and sizes: [fakeDim0 | 1] x [fakeDim1 | 1]
Coordinates:
Number Of Attributes: 4
  units : deg
  format : Float_32
  valid_range : -90.0...90.0
  hdf_name : Latitude_Start
(0,0) -80.90755
                                                     FYI: The
"Latitude_Stop" is -80.7469
                                                              The
"Longitude_Start" is -165.3068
                                                              The
"Longitude_Stop" is -167.3159
--------------------------------
ncl 4 > T = f->Temperature
ncl 5 > print(T)

Variable: T
Type: float
Total Size: 796 bytes
            199 values
Number of Dimensions: 2
Dimensions and sizes: [fakeDim20 | 1] x [fakeDim21 | 199]
Coordinates:
Number Of Attributes: 4
  units : degrees C
  format : Float_32
  valid_range : TBD
  hdf_name : Temperature
(0,0) -62.10014
(0,1) -62.15202
(0,2) -62.20389
(0,3) -62.25577
[SNIP--------------------------------]
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Received on Wed Apr 16 2008 - 10:18:24 MDT

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