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20020615: GEMPAK station location precision



The SF library routines currently store SLAT and SLON as integers (hundredths
of degrees). The library routines know inplicitly to multiply and divide by 100
to convert from the stored value and the actual value. This is aside from
the table reading routines for reading station tables.

One could change this for more precision, but in order to be able to recognize
other files, for example archives, case studies etc), you would have to ammend 
the
data management section of the surface file to reflect the scaling factor when
something other than 100 is used for backward compatibility.

Steve Chiswell
Unidata User Support




>From: Paul Ruscher <address@hidden>
>Organization: UCAR/Unidata
>Keywords: 200206151522.g5FFMEJ25051

>I would second this request; measurements to a precision of .0001 are
>easily available now at stations.  Of course the station table management
>would have to change and all routines that depend upon it.
>Micronets/Mesonets are becoming more commonplace for both University and
>operational met programs, and gempak still has lots of utility for data
>management/manipulation for these nets.  Paul
>
>On Fri, 14 Jun 2002, David Ovens wrote:
>
>> Gembuds,
>>
>> I'm interested in plotting mesonet data that can be down to .5 km from
>> another site and is often 1 to 5 km from another site.  At this high
>> resolution, mapping the data using SFMAP is not possible because
>> GEMPAK only uses 1/100 degree (approximately 1.1 km) precision for any
>> plotting of station data.  I've attempted to use higher precision when
>> creating a surface file from direct calls to GEMPAK routines in
>> FORTRAN but it gets lost, e.g., inputting 47.44472,-122.31361 for KSEA
>> still comes out as 47.440,-122.310.  And, of course, all of the
>> station tables in $GEMTBL/stns are hard-coded for just 2 decimal
>> places.
>>
>> Any chance we can increase this, if not easily for our own
>> distribution then in a future release?
>>
>> David
>> --
>>
>> David Ovens          e-mail: address@hidden
>> (206) 685-8108          plan: Real-time MM5 forecasting for Pacific Northwes
> t
>> Research Meteorologist
>> Dept of Atmospheric Sciences, Box 351640
>> University of Washington
>> Seattle, WA  98195
>>
>