Re: How to Extract and plot wind vectors in a box

You have used a graphical option (resource)

res@vcMinDistanceF = 0.025 ; thin out vectors

that does exactly what the the comment states ...
it 'thins' the vectors.

Comment or eliminate that line

    ;res@vcMinDistanceF = 0.025

On 4/7/12 2:01 AM, Ragi A.R wrote:
>
>
>
>
> Dear NCL users,
>
> I have a*.nc* file (*met_em_files* after WPS) which have U (wind) and V
> (Wind) values for the domain 7N-20N; 70E-80E and which is staggered. I
> want to extract and unstagger them (only u and v) and then plot (u,v)
> vector for the domain */8N; 76E-77E/* and *18N; 73E-74E* (domain
> attached /doc1.pdf/).
>
> The below is my approach (I modified the domain from 73E-77E and 78N-18N).
>
> But the issues are:
> 1). The vectors are not as expected. I have values at all grid points
> but only few vectors r there.
> 2). Not able to generate the box I wanted (as highlighted in doc1.pdf).
> 3). I wanted to plot the (u,v) vector at the four corners of the box.
>
> Can anyone suggest a solution to this?
>
>
> 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/wrf/WRFUserARW.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRF_contributed.ncl"
>
> begin
>
> a = addfile("met_em.d01.2009-04-01_00:00:00.nc <http://00.nc>","r")
>
>
> uu = wrf_user_getvar(a, "UU", 0)
> ua = uu(1,:,:)
> u = wrf_user_unstagger(ua,ua@stagger)
>
> vv = wrf_user_getvar(a, "VV", 0)
> va = vv(1,:,:)
> v = wrf_user_unstagger(va,va@stagger)
>
>
> wks = gsn_open_wks("ps", "uv_plot") ; open ps file
> gsn_define_colormap(wks,"gui_default") ; choose colormap
>
> res = True ; plot mods desired
> res@gsnMaximize = True ; maximize size
> res@gsnSpreadColors = True ; use full colormap
> res@gsnSpreadColorEnd = -2
> res@lbOrientation = "vertical" ; vertical label bar
> res@mpFillOn = True ; no map fill
> res@vcRefMagnitudeF = 5 ; make vectors larger
> res@vcRefLengthF = 0.025 ; ref vec length
> res@vcMinDistanceF = 0.025 ; thin out vectors
> res@vcGlyphStyle = "CurlyVector" ; choose wind barbs
> res@vcLabelsOn = True
> res@vcMonoLineArrowColor = False ; color barbs by scalar
>
> minlat = 8
> maxlat = 18
> minlon = 73
> maxlon = 77
>
> res@mpMinLatF = minlat
> res@mpMaxLatF = maxlat
> res@mpMinLonF = minlon
> res@mpMaxLonF = maxlon
> res@mpOutlineBoundarySets = "National"
> res@pmTickMarkDisplayMode = "Always"
> res@mpFillOn = False ; turn off map fill
> res@mpOutlineDrawOrder = "PostDraw"
>
> plot=gsn_csm_vector_map_ce(wks,u,v,res)
>
>
> end
>
>
> /-- /
> ///Regards,/
> /A.R.Ragi/
> /Research Scholar
> /
> /Centre for Atmospheric Sciences
> IIT Delhi, Hauz Khas
> New Delhi, India.
> /
> //
>
>
>
>
>
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Received on Sat Apr 7 07:41:14 2012