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7 Comments

  1. Michael Blaschek

    Hi.

    So I wanted to add a new topic, but the site says I'm not allowed to do that.

    Help?

     

    Thanks

     

  2. NEA MSS

    Same here. How I can plot a sub-selected variable from a GRIB file that is comprised of many other variables ?

  3. Eoin Whelan

    Hi Songhan,

    (I can't create a new topic either)

    I don't have a Magics answer for you but will make a suggestion using Metview:

    I use Metview macros in general for plotting. Most GRIB I plot are in files with more than one GRIB record. I use the following macro code to pick the GRIB record (parameter-number/level-type/level) I want to plot. It might be possible to translate this for use in Magics python/magml/...

    ...
    fcgrib = read  ( filename )
    #
    ## filter fcgrib here
    #
    getpar=grib_get_long(fcgrib, 'indicatorOfParameter')
    if type(getpar) = "string" then
      par=nil
      par=par&[getpar]
    else
      par=getpar
    end if
    gettyp=grib_get_long(fcgrib, 'indicatorOfTypeOfLevel')
    if type(getpar) = "string" then
      typ=nil
      typ=typ&[gettyp]
    else
      typ=gettyp
    end if
    getlev=grib_get_long(fcgrib, 'level')
    if type(getlev) = "string" then
      lev=nil
      lev=par&[getlev]
    else
      lev=getlev
    end if
    print (" harmoniePlot:: GRIBs found = " & count(par))
    pltgrb=1
    for i = 1 to count(par) do
      if  par[i] = parsel and typ[i] = typsel and lev[i] = levsel then
        pltgrb=i
        print (" harmoniePlot:: GRIB found at " & i)
      end if
    end for
    plot ( display_window[1], fcgrib[pltgrb])
    ...

  4. Iain Russell

    Hi Songhan, and thanks for your comment Eoin!

    Again, a reply that uses Metview - depending on how similar your GRIB files are to the ones archived at ECMWF, Metview's Grib Filter module can give an easy way to do it:

     

    all_data = read("/path/to/data.grb")

# filter Temperature at 1000hPa
filtered_data = read(
    levelist : 1000,
    param    : "t",
    data     : all_data
    )

plot(filtered_data)

    This does not work with all non-ECMWF data though.

    Outside of Metview, perhaps the GRIB_API tool grib_filter can do what you want, i.e. to filter out just the fields you want to plot.

    Best regards,

    Iain

     

  5. NEA MSS

    Thanks for the replies!

  6. Daniel Varela Santoalla

    I am afraid that the creation of topics is limited to people with write access to the wiki. But do drop an email to software.support@ecmwf.int and we can either create the topic for you or to answer the question directly

    Daniel

  7. mohamed koussaimi

    Hello,

    I want to plot wind from grib for forecast analysis but when i drag wind ploting icon and drop it on display window it doesn't work, please help me.