Re: NCL - Strange 'Noise' with plots (Installation trouble?)

Hello,

I have looked at the file you sent.

We can find no problems. The simple attached script
creates the two graphics files at:

http://www.cgd.ucar.edu/web/public_html/shea/Klee_hgt_bw.png
http://www.cgd.ucar.edu/web/public_html/shea/Klee_hgt_col.png

Perhaps it is an installation issue.

Regards
D
===========================================

>I am rather new to NCL, but learning eagerly. Additionally, my appologies
>if this is a duplicate post -- I have had trouble with geting the email
>size with attatchment down under the 100k limit.
>
>I have been encountering a rather strange problem that seems to be related
>to my installation of NCL.
>
>The problem I have been having is a seemingly random region of 'noise'
>amidst the plotted data. This occurs regardless of which forecast hour
>(which file) I plot, or within a given file, which parameter I plot, though
>the location and magnitude of the region of 'noise' varies. Illustrating
>this I have attached a zip of a sample image of 500 hpa heights from a 1deg
>GEFS mean grib forecast, along with the corresponding NCL script.
>
>I fellow (and more experienced) NCL user running Linux ran this script on
>his machine using a copy of the same grib file and had a perfect plot -- no
>'noise'. Further, using, degrib, I exported some of the same files'
>parameters to a shp file and examined them, finding the data to look good.
>As such, I am reasonably convinced that the problem does not lie in the
>grib file, or the script themselves (though I would happy to be proven
>wrong).
>
>Any thoughts or suggestions as to what I can check or more simply, how I
>can fix this problem?
>
>I am running NCL 4.2.0.a033 on a Windows XP machine under CYGWIN that was
>current as of less than a month ago (cygwin.exe v 1.5.24-2).
>Sincerely,
>
>
>
>Jacob Klee
>
>(See attached file: test_plot_bw.zip)
>
>
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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"

begin
  vNam = "HGT"
  plvl = 500 ; convenience/clarity ... use coordinate subscripting {..}

  f = addfile("/project/cas/shea/jacob_klee/geavg.t00z.pgrbaf06.grb","r")
  x = f->HGT_3_ISBL_10({plvl},:,:)

  printVarSummary(x)
  printMinMax(x, True)
  
  wks = gsn_open_wks("x11","tst")
  gsn_define_colormap (wks,"WhViBlGrYeOrRe")
  g7 = NhlNewColor(wks,0.7,0.7,0.7) ; add gray to colormap
   
  res = True
  res_at_tiMainString = vNam+": forecast_time="+x_at_forecast_time
  res_at_gsnCenterString = "initial time="+x_at_initial_time
  res_at_cnInfoLabelOrthogonalPosF = -0.07 ; move label inside plot
  res_at_mpLandFillColor = "grey" ; color of land
  plot = gsn_csm_contour_map_ce(wks, x ,res)

  res_at_cnFillOn = True
  res_at_cnLinesOn = False
  res_at_cnInfoLabelOn = False

  res_at_gsnMaximize = True
  res_at_gsnSpreadColors = True
  res_at_gsnSpreadColorStart = 6
  res_at_gsnSpreadColorEnd = -2 ; don't use gray for contouring

  res_at_mpFillOn = False ; continents will be colored over anyway

  res_at_lbLabelAutoStride = True ; let NCL select a nice stride

  plot = gsn_csm_contour_map(wks, x ,res)

end

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Received on Mon Mar 19 2007 - 16:23:58 MDT