[idvusers] HOW TO : Plot views across the prime meridian using IDV

[Don Murray]

Hi Ian-

Thanks for sharing this with the group.  This will be good for those
who want to subset the gridded datasets.

Now that I'm back from holiday, I've had a chance to work on the IDV 
side of this issue of the gap when the last grid point does not overlap
the first.  I just put out a new nightly build (2.5a1) that extends
the grid if need be so there is no longer a gap at the edge.  If
anyone wants to test that for me, I'd welcome feedback.  You can
download the latest nightly build from:

http://www.unidata.ucar.edu/downloads/idv

I've tested with the Global 2.5, 1.0 and .5 degree grids on our
UCAR server.

Don Murray

webmaster-IWC wrote:
> Hi all,
>  
> OK I have managed to get around this problem with plotting across the
> prime meridian - and it works, which did surprise me!
> So I thought I would share how this can be done.
>  
> Data set
> GFS global model 1x1 deg from NCEP
>  
> Software required
> IDV (unidata | display)
> Cnvgrib (NCO | convert grib 2 to grib 1)
> Convsh + Subset.tcl (BADC | create regional subsets into NetCDF)
>  
> 1. First download your data. You need to download the whole grid as
> cnvgrib will not work with partial downloading of grib files
> 2. Use Cnvgrib to convert grib 2 files into grib 1 (Example cnvgrib -g21
> gfs.t00z.pgrbf09.grib2 subset.grb)
> 3. Create a regional subset from the new grib 1 file data set (Example
> convsh subset.tcl -i subset.grb -o subset.nc -xs -60 -xe 60 -xi 1 -ys 0
> -ye 90 -yi 1)
>  
> The new subset file is now in NetCDF format with the starting grid lon @
> -60, this fixes the problem that IDV has plotting across the meridian.
>  
> FOR XP USERS ONLY.
>  
> I have complied copy of Cnvgrib.exe if any users require this.
>  
> Other programs and documents needed can be found below:
>  
> BADC
> HYPERLINK
> "http://badc.nerc.ac.uk/help/software/xconv/#utilites"http://badc.nerc.a
> c.uk/help/software/xconv/#utilites
> HYPERLINK
> "http://badc.nerc.ac.uk/help/software/xconv/subset.html"http://badc.nerc
> .ac.uk/help/software/xconv/subset.html
>  
> NCO
> HYPERLINK
> "http://www.nco.ncep.noaa.gov/pmb/codes/GRIB2/"http://www.nco.ncep.noaa.
> gov/pmb/codes/GRIB2/
>  
> Good luck and have fun
>  
> Ian
>  
>  
>  
>  
>  
>  
>  
> 
> No virus found in this outgoing message.
> Checked by AVG Free Edition. 
> Version: 7.5.516 / Virus Database: 269.17.13/1213 - Release Date:
> 07/01/2008 09:14
>  
> _______________________________________________
> idvusers mailing list
> idvusers at unidata.ucar.edu
> For list information, to unsubscribe, visit: http://www.unidata.ucar.edu/mailing_lists/ 

-- 
*************************************************************
Don Murray                               UCAR Unidata Program
dmurray at unidata.ucar.edu                        P.O. Box 3000
(303) 497-8628                              Boulder, CO 80307
http://www.unidata.ucar.edu/staff/donm
*************************************************************