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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> ncl-talk_at_ucar.edu
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Received on Wed Aug 06 2008 - 17:16:49 MDT