[gradsusr] high resolution file plotting constant value

Jennifer Adams jma at cola.iges.org
Thu Mar 14 12:25:29 EDT 2013


Hi, Carissa -- 
I can draw your temperature field on my mac laptop, but get the same error you do on my linux server ("Constant field. Value= 271.35"). There is a non-informative message "jpc_decode return" that comes from the grib2 library. The 'jpc_decode' routine is part of the jasper library, which is required by the grib2 library, but I can't find anything about it in the jasper documentation. In the library's code, there are comments that this routine is the JPEG-2000 decoder. So the problem likely has something to do with the JPEG compression. I have no idea why it would work on AIX and OSX but not linux, but I don't think ulimit or the GrADS version has anything to do with it (I was testing with GrADS 2.0.2, but the grib2 I/O code hasn't changed in a long time). Can you try using wgrib2 or some other tool to change the compression and see if that makes a difference? I don't have any other bright ideas … perhaps Wesley can be more helpful. 
--Jennifer



On Mar 14, 2013, at 11:17 AM, Carissa Klemmer - NOAA Federal wrote:

> Users,
> 
> I work for NCEP on the team that supports the operational NOMADS site. We are in the process of adding a new product to GrADS-OpenDAP but are running into issues. I have included the syntax for the control file used below to make the index file. Once the control and index file are created I attempt to view the data plotted through grads. 
> Here is the problem. I can not get the data to plot anything but a constant value on our sandbox nomads server or on my desktop. I can however see the plot successfully on our operational supercomputer. I have suspicions of the ulimit stack size, but have not been able to confirm this due to the test machines system constraints. So can anyone else get this data to successfully plot? If so please share your wisdom. Why does the exact same control file and grads version work on one system but not another?
> 
> The supercomputer is running grads version 2.0.a7 on AIX with ulimit -s of 4000000.
> NOMADS sandbox is running 2.0.a3.p3 on LINUX with ulimit -s of 16832
> I have downloaded both 2.0.2 and 2.0.a7 to my desktop (LINUX) with a ulimit -s 8000. 
> 
> 1. The grib2 file: rtgssthr_grb_0.083.grib2
> which can be found for download under: http://nomads.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/sst.20130313/
> 
> 2. The control file (sst.ctl) was created from g2ctl as follows:
> dset rtgssthr_grb_0.083.grib2
> index sst.idx
> undef 9.999E+20
> title /com/gfs/prod/sst.20130312/rtgssthr_grb_0.083.grib2
> * produced by g2ctl v0.0.8.2
> * command line options: /com/gfs/prod/sst.20130312/rtgssthr_grb_0.083.grib2
> * griddef=1:0:(4320 x 2160):grid_template=0:winds(N/S): lat-lon grid:(4320 x 2160) units 1e-06 input WE:NS output WE:SN res 48 lat 89.9                  58000 to -89.958000 by 0.083000 lon 0.042000 to 359.958000 by 0.083000 #points=9331200:winds(N/S)
> 
> dtype grib2
> ydef 2160 linear -89.958000 0.083
> xdef 4320 linear 0.042000 0.083000
> tdef 1 linear 00Z12mar2013 1mo
> zdef 1 linear 1 1
> vars 1
> TMPsfc   0,1,0   0,0,0 ** surface Temperature [K]
> ENDVARS
> 
> 3. to create the index file I ran:
> >gribmap -0 -v -i sst.ctl
> 
> 4.To view the output
> >grads
> >d tmpsfc
> 
> As even more proof that I somewhat know what I am doing, I can successfully create a control and index file using the same steps as above and view pretty graphics for the half degree SST, rtgssthr_grb_0.5.grib2. 
> 
> Thanks for any insight. 
> 
> -- 
> Carissa Klemmer 
> NCEP Central Operations 
> Production Management Branch Dataflow Team 
> 301-683-3835 _______________________________________________
> gradsusr mailing list
> gradsusr at gradsusr.org
> http://gradsusr.org/mailman/listinfo/gradsusr

--
Jennifer M. Adams
IGES/COLA
4041 Powder Mill Road, Suite 302
Calverton, MD 20705
jma at cola.iges.org



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