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19990804: GEMPAK/METAR question
- Subject: 19990804: GEMPAK/METAR question
- Date: Wed, 4 Aug 1999 10:57:01 -0600
Scot,
To view METAR data within Gempak, it must first be
decoded into a Gempak surface file.
Gempak requires prior conversion of the data from METAR into
a Gempak surface file since:
1) There is no station location information in a Metar observation.
METARs only contain a station ID, but no lat lon info. You have to
look up that information in a separate table- which takes time.
Gempak places all that info in the Gempak file once. If you
want "on-the-fly" displays, then you will be spending alot of
time looking for station locations.
2) Storing data into a decoded format is more efficient since you
only have to decode the data once. Retrieval from the data base
is much faster. On-the-fly decoding would be much slower.
The GEMPAK surface file is binary. I know that WXP uses an ASCII formatted
decoded file to use with its plot programs, it still must be decoded into
that format- but remains ASCII readable. WXP is available from Unisys.
Steve Chiswell
Unidata User Support
On Wed, 4 Aug 1999, Scot Loehrer wrote:
> Steve,
>
> A quick question from across the hall...
>
> For one of our field programs I have made available
> files containing regular ASCII METAR formatted surface
> observations (each file contains the data for one
> site over the duration of the project).
>
> I have received a request for a software package that
> can generate displays of these data without any prior
> manipulation of the data files.
>
> Can one use GEMPAK to directly use these files to
> generate displays of the data?
>
> If not, can GEMPAK utilize ASCII METAR formatted data
> set up in some other file structure (i.e. files by
> day or hour)?
>
> Or, does the ASCII METAR formatted data have to be
> converted to some other format prior to the data being
> usable by GEMPAK?
>
> Do you happen to know of any software packages that
> utilize ASCII METAR formatted data directly to develop
> displays?
>
> Thanks for any help.
>
> Scot Loehrer
> UCAR/JOSS
>