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Help with setgrid

Added by Alex Petkov over 4 years ago

I have data which is referenced with longitudes b/n 220 and 300 deg on a regular 0.25 deg grid. I would like to set the grid to -140 to -60 lon range

The data has its grid defined as follows:

cdo griddes ../data/gfs/TMP/gfs.t00z.pgrb2.0p25.f003.grb2
#
# gridID 1
#
gridtype  = lonlat
gridsize  = 40125
xsize     = 321
ysize     = 125
xname     = lon
xlongname = "longitude" 
xunits    = "degrees_east" 
yname     = lat
ylongname = "latitude" 
yunits    = "degrees_north" 
xfirst    = 220
xinc      = 0.25
yfirst    = 22
yinc      = 0.25

As I understand, changing xfirst to -140 should accomplish what I need, but the grid remains unchanged (even changed xunits = degrees_west):

cat mygrid
#
# gridID 1
#
gridtype  = lonlat
gridsize  = 40125
xname     = lon
xlongname = longitude
xunits    = degrees_west
yname     = lat
ylongname = latitude
yunits    = degrees_north
xsize     =  321
ysize     =  125
xfirst    =  -140
xinc      =  0.25
yfirst    =  22
yinc      =  0.25

cdo -setgrid,mygrid ../data/gfs/TMP/gfs.t00z.pgrb2.0p25.f003.grb2 out.grb

cdo sinfon out.grb 
...
Grid coordinates :
     1 : lonlat                   : points=40125 (321x125)
                              lon : 220 to 300 by 0.25 degrees_east
                              lat : 22 to 53 by 0.25 degrees_north
...

Any ideas? The file in question is attached.

Thank you very much in advance!!
Alex


Replies (2)

RE: Help with setgrid - Added by Karin Meier-Fleischer over 4 years ago

Hi Alex,

it seems to be a GRIB2 issue because GRIB1 and netCDF don't have problems setting the longitudes to negative values. But I'm not a GRIB expert.

cdo -copy -setgrid,mygrid.txt gfs.t00z.pgrb2.0p25.f003.grb2 outfile.grb2
cdo sinfon outfile.grb2
   File format : GRIB2
    -1 : Institut Source   T Steptype Levels Num    Points Num Dtype : Parameter name
     1 : NCEP     unknown  v instant       1   1     40125   1  P9   : 2t            
   Grid coordinates :
     1 : lonlat                   : points=40125 (321x125)
                              lon : 220 to 300 by 0.25 degrees_east
                              lat : 22 to 53 by 0.25 degrees_north
   Vertical coordinates :
     1 : height                   : levels=1
                           height : 2 m
   Time coordinate :  1 step
     RefTime =  2019-09-20 00:00:00  Units = hours  Calendar = proleptic_gregorian
  YYYY-MM-DD hh:mm:ss  YYYY-MM-DD hh:mm:ss  YYYY-MM-DD hh:mm:ss  YYYY-MM-DD hh:mm:ss
  2019-09-20 03:00:00
cdo sinfon: Processed 1 variable over 1 timestep [0.05s 33MB]
cdo -f grb -copy -setgrid,mygrid.txt gfs.t00z.pgrb2.0p25.f003.grb2 outfile.grb
cdo sinfon outfile.grb
   File format : GRIB
    -1 : Institut Source   T Steptype Levels Num    Points Num Dtype : Parameter name
     1 : NCEP     unknown  v instant       1   1     40125   1  P9   : var0          
   Grid coordinates :
     1 : lonlat                   : points=40125 (321x125)
                              lon : -140 to -60 by 0.25 degrees_east
                              lat : 22 to 53 by 0.25 degrees_north
   Vertical coordinates :
     1 : height                   : levels=1
                           height : 2 m
   Time coordinate :  1 step
     RefTime =  2019-09-20 00:00:00  Units = hours  Calendar = proleptic_gregorian
  YYYY-MM-DD hh:mm:ss  YYYY-MM-DD hh:mm:ss  YYYY-MM-DD hh:mm:ss  YYYY-MM-DD hh:mm:ss
  2019-09-20 03:00:00
cdo sinfon: Processed 1 variable over 1 timestep [0.05s 24MB]
cdo -f nc -copy -setgrid,mygrid.txt gfs.t00z.pgrb2.0p25.f003.grb2 outfile.nc
cdo sinfon outfile.nc
   File format : NetCDF2
    -1 : Institut Source   T Steptype Levels Num    Points Num Dtype : Parameter name
     1 : NCEP     unknown  v instant       1   1     40125   1  F32  : 2t            
   Grid coordinates :
     1 : lonlat                   : points=40125 (321x125)
                              lon : -140 to -60 by 0.25 degrees_east
                              lat : 22 to 53 by 0.25 degrees_north
   Vertical coordinates :
     1 : height                   : levels=1
                           height : 2 m
   Time coordinate :  1 step
     RefTime =  2019-09-20 00:00:00  Units = hours  Calendar = proleptic_gregorian
  YYYY-MM-DD hh:mm:ss  YYYY-MM-DD hh:mm:ss  YYYY-MM-DD hh:mm:ss  YYYY-MM-DD hh:mm:ss
  2019-09-20 03:00:00
cdo sinfon: Processed 1 variable over 1 timestep [0.00s 22MB]

-Karin

RE: Help with setgrid - Added by Alex Petkov over 4 years ago

Thank you Karin for your help!!

I will switch to nc format and see how it goes--the data is to be served through Geoserver.

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