stnmap [ -i fname ]
stnmap is a GrADS utility that writes out a hash
table
and/or link list information for station data that allows
GrADS to access the report data more efficiently.
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 - the new number of times for
example - and then rerun the stnmap utility.
Note the difference between station descriptor file and a grid descriptor file:
DTYPE specify a data
type of: station
STNMAP gives the file
name of the station mapping file.
XDEF, YDEF, ZDEF not
specified.
TDEF describes the
time grouping interval and
the number of the time groups in the
file.
VAR surface
variables must come first, and
are given a zero for the
number-of-levels field. Level dependent
variables are listed after the surface
variables, and are given a one in the
number-of-levels field.
ua.reps is written, and
the
descriptor file stat.ctl, including the information
records
for the station data file ua.reps is created, you
should
then create the station map file ua.map (named in the
STNMAP
record of the descriptor file; see below) by running the
stnmap utility.
Example descriptor file: stat.ctl
DSET ^ua.reps
DTYPE station
STNMAP ^ua.map
UNDEF -999.0
TITLE Real Time Upper air obs
TDEF 10 linear 12z18jan1992 12hr
VARS 12
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
Running 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.