[ncl-talk] reading GRIB2 files
Matt Flournoy
mflournoy37 at gmail.com
Tue Sep 8 10:29:25 MDT 2015
Hi all,
Adam, thank you for helping with this. First, I entered the setfileoption
line that you sent, but that didn't fix the problem or change the warning
that I get:
"warning:getfilevarnames: rap_130_20150706_0000_000 contains no variables
readable by NCL".
Then, I redownloaded the data file and worked with that, but still do not
get any variable names from the file. As before, when I read the file in
the exact same way that you do, I only get a missing value for varnames.
Do you, or anyone else, have any ideas about where to go from here?
Thanks again,
Matt
On Fri, Sep 4, 2015 at 10:18 AM, Adam Phillips <asphilli at ucar.edu> wrote:
> Hi Matt,
> Thanks for sending your complete code along with a pointer to the file. I
> was able to read your file into NCL v6.2.1 and v6.3.0 here, so I would
> suggest making sure you downloaded the entire file and/or redownload the
> file. Here's what I did:
>
> a = addfile("Downloads/rap_130_20150706_0000_000.grb2","r")
> varnames = getfilevarnames(a)
> print(varnames)
>
> Variable: varnames
> Type: string
> Total Size: 816 bytes
> 102 values
> Number of Dimensions: 1
> Dimensions and sizes: [102]
> Coordinates:
> (0) TMP_P0_L1_GLC0
> (1) TMP_P0_L7_GLC0
> (2) TMP_P0_L100_GLC0
> (3) TMP_P0_L103_GLC0
> (4) TMP_P0_2L108_GLC0
> (5) POT_P0_L7_GLC0
> (6) POT_P0_L103_GLC0
> (7) EPOT_P0_L1_GLC0
> (8) DPT_P0_L103_GLC0
> (9) DEPR_P0_L103_GLC0
> (10) SPFH_P0_L103_GLC0
> (11) RH_P0_L4_GLC0
> .....
>
>
> I searched the NCL website for "RUC" and got pointed to skewt example #6
> here:
> http://www.ncl.ucar.edu/Applications/skewt.shtml#ex6
>
> Looking at that code, they add a setfileoption:
>
> setfileoption("grb","SingleElementDimensions","Initial_time")
>
>
> As you can see I did not need that setfileoption to open the file correctly, but perhaps for some reason your set up does?
>
> Hope that helps, if you continue to have trouble with the file let the ncl-talk email list know.
>
> Adam
>
>
>
>
>
>
> On Fri, Sep 4, 2015 at 8:56 AM, Matt Flournoy <mflournoy37 at gmail.com>
> wrote:
>
>> Hi all,
>>
>> Does anyone have experience reading RUC GRIB2 files? I'm trying to read
>> GRIB2 output from 13km RUC model data, which is available on the NOMADS
>> site (http://nomads.ncdc.noaa.gov/data.php#hires_weather_datasets).
>> Specifically, I am trying to read files from 06 July 2015, but I suspect
>> this problem is universal among at least all of the 13km RUC GRIB2 output
>> files.
>>
>> I've tried a couple ways to read the GRIB2 data, including reading the
>> GRIB2 file and also trying to convert the GRIB2 file to netcdf. When I try
>> to read the GRIB2 data directly (specifically
>> "rap_130_20150706_0000_000.grb2"), I get the following warning message:
>>
>> warning:getfilevarnames: rap_130_20150706_0000_000 contains no variables
>> readable by NCL
>>
>> I've pasted my NCL script that yields this warning at the bottom of my
>> message.
>>
>> Second, when I try to convert the GRIB2 file to netcdf using
>> "ncl_convert2nc" in the command line, I get this similar warning:
>>
>> warning:getfilevarnames: rap_130_20150706_0000_000 contains no variables
>> readable by NCL
>> ./rap_130_20150706_0000_000.grb2 contains no variables readable by NCL:
>> converting global attributes only
>>
>> Then, when I "ncl_filedump" the created netcdf file, I get this:
>>
>> Variable: f
>> Type: file
>> filename: rap_130_20150706_0000_000
>> path: rap_130_20150706_0000_000.nc
>> file global attributes:
>> creation_date : Fri Sep 4 09:52:47 CDT 2015
>> NCL_Version : 6.2.1
>> system : Linux bigbang.protect.nssl 2.6.32-504.12.2.el6.x86_64 #1
>> SMP Sun Feb 1 12:14:02 EST 2015 x86_64 x86_64 x86_64 GNU/Linux
>> Conventions : None
>> grib_source : rap_130_20150706_0000_000.grb2
>> title : NCL: convert-GRIB-to-netCDF
>> dimensions:
>> variables:
>>
>> Do you know how to address this issue? I am currently using NCL version
>> 6.2.1 on bigbang, and this problem also appears in other NCL versions.
>>
>> Thank you,
>> Matt
>>
>>
>>
>> ------------ begin NCL script ---------------
>>
>>
>> ;******************************************************************************;
>> ; Load libraries.
>>
>> ;******************************************************************************;
>>
>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/shea_util.ncl"
>>
>>
>> ;-----------------------------------------------------------------------------;
>> ; Synoptic overview plots of the July 06 2015 case from the RUC.
>>
>> ;-----------------------------------------------------------------------------;
>>
>> begin
>>
>> ruc_filepath =
>> ("/home/matt.flournoy/PECAN/overview/data/RUC_data/rap_130_20150706_0000_000.grb2")
>> ruc_file = addfile(ruc_filepath,"r")
>>
>> varnames = getfilevarnames(ruc_file)
>>
>> if(.not.any(ismissing(varnames))) then
>>
>> do i=0,dimsizes(varnames)-1
>>
>> printFileVarSummary(ruc_file,varnames(i))
>>
>> end do
>>
>> end if
>>
>> end
>>
>> --------------- end NCL script ----------------
>>
>> --
>> Matthew Flournoy
>> M.S. Meteorology Candidate, University of Oklahoma
>> B.S. Meteorology, Penn State University
>>
>> _______________________________________________
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>>
>>
>
>
> --
> Adam Phillips
> Associate Scientist, Climate and Global Dynamics Laboratory, NCAR
> www.cgd.ucar.edu/staff/asphilli/ 303-497-1726
>
> <http://www.cgd.ucar.edu/staff/asphilli>
>
--
Matthew Flournoy
M.S. Meteorology Candidate, University of Oklahoma
B.S. Meteorology, Penn State University
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