Resource: grid_num

The grid_num resource is used to specify the exact grid in a file to retrieve. Each grid is numbered from 0 - N and the grid number can be inquired with the griblook program. Use this number to access the specific grid.

The format of the resource is as follows:

+time:level:var[:units]
or
#num[:units]

The value of num represents the sequence number of the grid in the file.  Grids are numbered starting at 0 (zero).

The values of time, level, and var make it possible to specify the grid based on typical grid information.  Any valid forecast time, level and variable can be specified.  Possible values for each are:

• time: init,06,12,18,24,30,36,42,48,60,72,d3,d4,d5,d6,d7,d8,d9,d10
• level: sfc, sl (sea level), trop, mwnd, 1000, 850, 700, 500, 400, 300, 200, 100
• var: temp, rhum, pres, vvel, uwnd, vwnd, prec, lift

If the grid type is unknown, it can be obtained using the griblook program:

griblook -cu -mo=eta -me=out3

      GRID FILE PARSER (Ver 5.0-X11)

Current filename: /home/wxp/hds/97092900_eta.grb
Reading from grid file:/home/wxp/hds/97092900_eta.grb
  0: ETA analysis for 0000Z 29 SEP 97-100 mb Vertical velocity (Pa/s)
     Model: ETA  Time: init         Level: 100mb        Variable: vvel    Units: Pa/s