Re: [idvusers] Problem viewing LAPS GRIB2 data

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/
===============================================================================