Re: plotting wind between two values

Dear Ahmed

How about masking the data before you plot it?
Something like

  u = a->U(1,:,:)
  v = a->V(1,:,:)
  wspd = sqrt(u*u+v*v)
  u=mask(u,wspd.gt.5.,True)
  v=mask(v,wspd.gt.5.,True)

All winds above 5 m/s will be masked and thus not visible on your plot.

Maybe this is what you were after?
Regards, Andrea

Andrea N. Hahmann
Senior Scientist
DTU Wind Energy

Technical University of Denmark
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Department of Wind Energy
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Direct +45 46775471
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From: ahmed lasheen <ahmed4kernel@gmail.com<mailto:ahmed4kernel@gmail.com>>
Date: Sat, 21 Apr 2012 00:39:26 +0200
To: Mary Haley <haley@ucar.edu<mailto:haley@ucar.edu>>
Cc: ncl forum <ncl-talk@ucar.edu<mailto:ncl-talk@ucar.edu>>
Subject: Re: plotting wind between two values

I have attached the script (it is taken form example vector_3.ncl)
and I have also attached the data file (and It is also on the NCL website).
thanks in advance

On Sat, Apr 21, 2012 at 12:20 AM, Mary Haley <haley@ucar.edu<mailto:haley@ucar.edu>> wrote:
I will have to defer you to Dave Brown then. With the weekend coming up, we may not get an answer to you before Monday.

It will help if you can provide a script and some data for Dave. See our ftp information at:

http://www.ncl.ucar.edu/report_bug.shtml#HowToFTP

--Mary

On Apr 20, 2012, at 11:56 AM, ahmed lasheen wrote:

> thnaks for your reply
> I try it ,but it didnot work ,still all vectors of all magnitudes are rendered
>
> On Fri, Apr 20, 2012 at 7:34 PM, Mary Haley <haley@ucar.edu<mailto:haley@ucar.edu>> wrote:
> These vector levels do not represent absolute begin and end values of the vectors you want to see. They simply represent what vector levels to span through the full range of your data.
>
> Maybe what you need to set are vcMinMagnitudeF and vcMaxMagnitudeF.
>
> --Mary
>
>
> On Apr 20, 2012, at 3:26 AM, ahmed lasheen wrote:
>
> > Hello
> > My question is that i am trying to plot the wind values just between two values(e.g between 0 and 5 m/s)
> > so that I used
> > vcres@vcMinLevelValF = 0 ; m/s
> > vcres@vcMaxLevelValF =5; m/s
> > But it didn't work(all wind of all values are plotted not only the wind between these two values)
> > I expect to see wind plotted only in some region which satisfy this criteria.
> >
> > thanks in advance
> >
> > On Fri, Apr 20, 2012 at 12:03 AM, Mary Haley <haley@ucar.edu<mailto:haley@ucar.edu>> wrote:
> > You need to be more specifc about what doesn't work. Do you mean the plot is incorrect? Are you getting an error when you run the script?
> >
> > You could try adding a spacing, just in case:
> >
> > vcres@vcLevelSpacingF = 1
> >
> >
> > On Apr 18, 2012, at 10:12 AM, ahmed lasheen wrote:
> >
> > > Hello
> > > I am trying to plot wind between two values using the resources
> > > vcres@vcLevelSelectionMode ="ManualLevels"
> > > vcres@vcMinLevelValF = 0
> > > vcres@vcMaxLevelValF =5
> > > but it doesnot work
> > > any suggestion?
> > > the script , I download it from the NCL website and i just add the previous three line to it .
> > > ----------------------------------------------------------------------
> > > ; vector_3.ncl
> > > ;
> > > ; Concepts illustrated:
> > > ; - Drawing a black-and-white vector plot over a cylindrical equidistant map
> > > ; - Adding a time stamp to a plot
> > > ; - Thinning vectors using a minimum distance resource
> > > ; - Moving the vector reference annotation to the top right of the plot
> > > ;----------------------------------------------------------------------
> > > 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"
> > > ;************************************************
> > > begin
> > > ;************************************************
> > > ; read in netCDF file
> > > ;************************************************
> > > a = addfile("uv300.nc<http://uv300.nc>","r")
> > > ;************************************************
> > > ; read in zonal [u] and meridional [v] winds (July)
> > > ;************************************************
> > > u = a->U(1,:,:)
> > > v = a->V(1,:,:)
> > > ;************************************************
> > > ; create plot
> > > ;************************************************
> > > wks = gsn_open_wks("x11","vector") ; open a ps file
> > >
> > > vcres = True ; plot mods desired
> > > vcres@gsnFrame = False ; so we can draw time stamp
> > > vcres@vcRefAnnoOrthogonalPosF = -1.0 ; move ref vector up
> > > vcres@vcRefMagnitudeF = 10.0 ; define vector ref mag
> > > vcres@vcRefLengthF = 0.045 ; define length of vec ref
> > > vcres@vcGlyphStyle = "CurlyVector" ; turn on curly vectors
> > > vcres@vcMinDistanceF = 0.017
> > >
> > > vcres@vcLevelSelectionMode ="ManualLevels"
> > > vcres@vcMinLevelValF = 0 ; m/s
> > > vcres@vcMaxLevelValF =5; m/s
> > >
> > > vector = gsn_csm_vector_map_ce(wks,u,v,vcres)
> > > ;************************************************
> > > ; add time stamp to plot
> > > ;************************************************
> > > infoTimeStamp(wks,0.025,"uv300.nc<http://uv300.nc>") ; arguments are workstation
> > > ; size of text desired, and
> > > ; right string.
> > > frame (wks)
> > > end
> > >
> > > thanks in advance
> > > --
> > > ===============
> > > Ahmed Lasheen
> > > Junior researcher at Cairo Numerical Weather Prediction Center (CNWPC)
> > > Egyptian Meteorological Authority(EMA)
> > > Cairo,Egypt
> > > ===============
> > >
> > > _______________________________________________
> > > ncl-talk mailing list
> > > List instructions, subscriber options, unsubscribe:
> > > http://mailman.ucar.edu/mailman/listinfo/ncl-talk
> >
> >
> >
> >
> > --
> > ===============
> > Ahmed Lasheen
> > Junior researcher at Cairo Numerical Weather Prediction Center (CNWPC)
> > Egyptian Meteorological Authority(EMA)
> > Cairo,Egypt
> > ===============
> >
> > _______________________________________________
> > ncl-talk mailing list
> > List instructions, subscriber options, unsubscribe:
> > http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>
>
>
>
> --
> ===============
> Ahmed Lasheen
> Junior researcher at Cairo Numerical Weather Prediction Center (CNWPC)
> Egyptian Meteorological Authority(EMA)
> Cairo,Egypt
> ===============
>
> _______________________________________________
> ncl-talk mailing list
> List instructions, subscriber options, unsubscribe:
> http://mailman.ucar.edu/mailman/listinfo/ncl-talk

--
===============
Ahmed Lasheen
Junior researcher at Cairo Numerical Weather Prediction Center (CNWPC)
Egyptian Meteorological Authority(EMA)
Cairo,Egypt
===============