[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

20051016: Gempak - Extracting point data from GEMPAK grid

>From: "John Meyers" <address@hidden>
>Organization: UCAR/Unidata
>Keywords: 200510170024.j9H0Oc6B007461

>Institution: Museum of Science, Boston MA
>Package Version: 5.8.3a
>Operating System: RHEL4
>Hardware Information: Dual Opteron
>Inquiry: In order to import some data into Flash format for our website, I nee
> d to extract individual parameter values at specific coordinates in Gempak gr
> ids (or NetCDF if not possible in Gempak).  For example, how can I return the
>  surface temperature at a specific lat/lon point in the RUC2 grid for a speci
> fic forcast hour?  I've looked at GDLIST but can't quite figure out how to do
>  it for one point.
>

John,

The easiest way to extract grid point data for a level/time at a specific
station or lat/lon is to use the program GDPOINT.


 GEMPAK-GDPOINT>l
 GDATTIM  = f000
 GDFILE   = ruc2
 GLEVEL   = 2
 GPOINT   = bos
 GVCORD   = hght
 GFUNC    = tmpf
 SCALE    = 0
 GEMPAK-GDPOINT>r
 
GDFILE: $MODEL/ruc/2005101715_ruc236.gem                  
GPOINT: bos                                               
GVCORD: hght                                              
GLEVEL: 2                                                 
GFUNC : tmpf                                              
SCALE : 0                                                 
     051017/1500F000 :     54.82568

or

GDATTIM = FALL
 GEMPAK-GDPOINT>r
 
GDFILE: $MODEL/ruc/2005101715_ruc236.gem                  
GPOINT: bos                                               
GVCORD: hght                                              
GLEVEL: 2                                                 
GFUNC : tmpf                                              
SCALE : 0                                                 
     051017/1500F000 :     54.82568
     051017/1500F001 :     56.78081
     051017/1500F002 :     57.28056
     051017/1500F003 :     57.80221
     051017/1500F004 :     58.20769
     051017/1500F005 :     58.04918
     051017/1500F006 :     56.89297
     051017/1500F009 :     52.16292

This method would be easy to implement in a CGI or other request process.

If you were to need many stations converted at one time, then you can
use GDGSFC to interpolate grid point data to a surface file at station locations
for retreival with SFLIST.

Steve Chiswell
Unidata User Support

>
>
--
NOTE: All email exchanges with Unidata User Support are recorded in the
Unidata inquiry tracking system and then made publicly available
through the web.  If you do not want to have your interactions made
available in this way, you must let us know in each email you send to us.