stnmap

stnmap is an external GrADS utility that writes out a hash table and/or link list information for station data that allows GrADS to access the data more efficiently. After a station data set has been written and the accompanying data descriptor file has been created, you must run the stnmap utility before you can look at the data in GrADS.

The stnmap options are as follows:

fname
The name of the station data descriptor file. If not specified, stnmap will prompt the user.

-0

Allows processing of certain templated station data sets without actually reading the data.

The output from stnmap goes into a file that is named in the STNMAP record of the data descriptor file. (See Usage Note #2).

Usage Notes

1. If you change the data file (perhaps by appending another time group), you will also have to change the descriptor file to reflect the changes and then rerun the stnmap utility.

2. Note the difference between required records in a station descriptor file and a grid descriptor file:

   DTYPE

   specifies a data type of: station
   STNMAP
   gives the file name of the station mapping file
   XDEF, YDEF, ZDEF
   these records are not specified in a station data control file
   TDEF
   describes the time grouping interval and the number of the time groups in the file
   VARS
   surface variables are listed first, and show a "0" for the number-of-levels field. Level-dependent variables are listed after the surface variables, and show a "1" in the number-of-levels field.

Examples

Here's a sample descriptor file stat.ctl for station data set ua.reps:

DSET   ^ua.reps
DTYPE  station
STNMAP ^ua.map
UNDEF  -999.0
TITLE  Real Time Upper air obs
TDEF   10 linear 12z18jan1992 12hr
VARS   8
  slp 0 99 SLP
  ts  0 99 Temps
  us  0 99 U Winds
  vs  0 99 V Winds
  z   1 99 Heightsa
  t   1 99 Temps
  u   1 99 U Winds
  v   1 99 V WInds
ENDVARS


Run the stnmap utility:

stnmap -i stat.ctl

The station map file ua.map is a binary file, which includes the hash table and/or link list information.