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Re: [idvusers] Problem viewing LAPS GRIB2 data

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  • Subject: Re: [idvusers] Problem viewing LAPS GRIB2 data
  • Date: Fri, 23 Apr 2010 13:48:24 -0600 (MDT)

On Thu, 15 Apr 2010, Matt Foster wrote:


Robb Kambic wrote:

Matt,

In viewing some of the data in the file, the sw corner comes out to be
La1 = 30.335892
Lo1 = 255.35483
What do you expect the lat/lon of the ne corner to be? Also do you have a correct sample image? 

Thanks,
Robb...



Robb,
Output gleaned from wgrib2 indicates that the NE corner is 39.598, -90.919. The SW corner is correct. 

Matt,

The wgrib2 dump of your sample file:
./wgrib2 -domain /local/robb/data/grib/laps/100981200.gr2

1:0:N=39.980996 S=30.335222 W=-106.003234 E=-90.927059
2:3447:N=39.980996 S=30.335222 W=-106.003234 E=-90.927059
...

so the sw corner is 30.335, -106.003234

but reading the sample file:
La1 = 30.335892
Lo1 = 255.35483  == -104,64517

the Lo1 are different, wgrib2 -106.003234 grib library -104,64517
Since both the grib library and gempak agree, there might be something wrong with wgrib2. I believe that's the reason the NE corner is different. 



RObb...
I also just found that if I decode the grib2 file and display the data with GEMPAK, I get the same sort of output that IDV gives me. This leads me to believe it's something in the grib2 message itself that's causing this.
I don't understand why wgrib2 would give me the correct NE corner, but the data does not display correctly. 

Matt


--
Do not go where the path may lead; go instead where there is no path and leave a trail. 
-- Ralph Waldo Emerson




===============================================================================
Robb Kambic                                Unidata Program Center
Software Engineer III                      Univ. Corp for Atmospheric Research
address@hidden             WWW: http://www.unidata.ucar.edu/
===============================================================================