Re: the longitude problem when read grib format data

Hi Dave,

 You are right! The output show lon: [ 0..358.125] after I updated the NCL version. Thus the wrong longitude is just because I use the old version of ncl 4.2.0_a033 .

Thanks a lot,
Li

----- Original Message -----
  From: David Brown
  To: lizhou
  Cc: ncl-talk_at_ucar.edu
  Sent: Wednesday, August 06, 2008 1:16 PM
  Subject: Re: the longitude problem when read grib format data

  Hi Li,
  What version of NCL are you using?
  When I run your code using the current version of NCL, I get the following output.
  Variable: lcld
  Type: float
  Total Size: 14943744 bytes
              3735936 values
  Number of Dimensions: 4
  Dimensions and sizes: [initial_time0_hours | 23] x [forecast_time1 | 9] x [lat_98 | 94] x [lon_98 | 192]
  Coordinates:
              initial_time0_hours: [1588776..1781616]
              forecast_time1: [1..9]
              lat_98: [88.54195..-88.54195]
              lon_98: [ 0..358.125]
  Number Of Attributes: 9
    sub_center : Environmental Modeling Center
    center : US National Weather Service - NCEP (WMC)
    long_name : Total cloud cover
    units : %
    _FillValue : -999
    level_indicator : 214
    gds_grid_type : 4
    parameter_table_version : 2
    parameter_number : 71

  The coordinate variable lon_98 ranges from 0 to 358.125 in the file.
  Its attribute Lo2 is set to -1.875 because that is how it is encoded into the GRIB file, but
  the coordinate values are correctly calculated.

  You must be using an old version of NCL. It does appear that a change was made between versions 4.2.0_a034 and 4.3.0 that
  most likely affected this problem.
   -dave

  On Aug 5, 2008, at 8:46 PM, lizhou wrote:

    Dear all,

     when I read CFS output with grib format, I got wrong longitude. the longitude is "lon_98: [ 0..1.875]" instead of beginning with 0 with 1.875 step. does anyone know what's happen?

    Thanks in advance,
    Li
    -------------------------------------

    The read code is:
    load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
    load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
    load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"

     begin
       in = addfile("data/lcld.ensm.apr.cfs.data.grb","r")
       lcld = in->T_CDC_98_LCY_ave1m
       printVarSummary(lcld)
    end

    The output information is:
    Variable: lcld
    Type: float
    Total Size: 14943744 bytes
                3735936 values
    Number of Dimensions: 4
    Dimensions and sizes: [initial_time0 | 23] x [forecast_time1 | 9] x [lat_98 | 94] x [lon_98 | 192]
    Coordinates:
                initial_time0: [04/01/1981 (00:00)..04/01/2003 (00:00)]
                forecast_time1: [1..9]
                lat_98: [88.54195..-88.54195]
                lon_98: [ 0..1.875]
    Number Of Attributes: 9
      sub_center : Environmental Modeling Center
      center : US National Weather Service - NCEP (WMC)
      long_name : Total cloud cover
      units : %
      _FillValue : -999
      level_indicator : 214
      gds_grid_type : 4
      parameter_table_version : 2
      parameter_number : 71

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Received on Wed Aug 06 2008 - 21:08:27 MDT