Re: Visualizing NARR storm motion vectors

Hi Jamie,

You have 2 draw(plot) lines in your code:

     polyres_at_gsMarkerColor = "black"
     draw(plot)
     gsn_polymarker(wks,plot,lon,lat,polyres)

and then

     overlay(plot,vctrplot)
     draw(plot)
     gsn_polymarker(wks,plot,lon,lat,polyres)

You should definitely delete the first draw(plot) line. Also, the order
that you should use for your plot calls and gsn_polymarker calls is:

1) plot = gsn_csm_contour_map(wks,speed,res)
2) vctrplot = gsn_csm_vector(wks,upt,vpt,resvctr)
3) overlay(plot,vctrplot)
4) gsn_polymarker(wks,plot,lon,lat,polyres)
5) frame(wks)

Finally, note that you can use gsn_csm_vector_scalar_map to plot the
vectors over a scalar field (wind speed in your case).

http://www.ncl.ucar.edu/Applications/vector.shtml#ex1

Adam

Jamie Lahowetz wrote:
> Hello,
> I have been trying to visualized NARR storm vectors but am getting
> confused. I want one output (I get two right now and dont know why) and
> I'm just not sure if I have coded it right.
>
>
>
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
>
> ;############################
>
> begin
>
> fili =
> "/home/jlahowet/THOR/test2/narr/u-v_comp/narr-a_221_20080522_1800_000.grb"
> f = addfile (fili, "r")
>
> ;############################
> ; Print
> ;############################
>
> names = getfilevarnames(f)
> print(names)
> atts = getfilevaratts(f,names(0))
> dims = getfilevardims(f,names(0))
> print(atts)
> print(dims)
>
> ;############################
> ; Variables
> ;############################
>
> upt = f->USTM_221_HTGY
> vpt = f->VSTM_221_HTGY
> lat2d = f->gridlat_221
> lon2d = f->gridlon_221
>
> upt_at_lat2d = lat2d
> upt_at_lon2d = lon2d
> vpt_at_lat2d = lat2d
> vpt_at_lon2d = lon2d
>
> ;############################
> ; Calculations for Vectors
> ;############################
>
> speed = sqrt(upt(:,:)^2+vpt(:,:)^2)
>
> ;############################
>
> ;wks = gsn_open_wks("x11","vectors")
> wks = gsn_open_wks("pdf","vectors")
> gsn_define_colormap(wks,"gui_default")
>
> ;############################
> ; Resources
> ;############################
>
> res = True
> res_at_tiMainString = "Native Lambert Conformal"
>
> res_at_mpLimitMode = "Corners"
> res_at_mpLeftCornerLatF = 37.0
> res_at_mpLeftCornerLonF = -103.0
> res_at_mpRightCornerLatF = 40.0
> res_at_mpRightCornerLonF = -98.0
>
> res_at_mpProjection = "LAMBERTCONFORMAL"
> res_at_mpLambertParallel1F = lon2d_at_Latin1
> res_at_mpLambertParallel2F = lon2d_at_Latin2
> res_at_mpLambertMeridianF = lat2d_at_Lov
>
> ; print(lon2d_at_Latin1)
> ; print(lon2d_at_Latin2)
> ; print(lon2d_at_Lov)
>
> res_at_pmTickMarkDisplayMode = "Always"
> res_at_mpFillOn = False
> res_at_mpOutlineDrawOrder = "PostDraw"
> res_at_mpOutlineBoundarySets = "GeophysicalAndUSStates"
> res_at_mpGridAndLimbOn = True
>
> res_at_tfDoNDCOverlay = False
>
> res_at_cnFillOn = True
> res_at_cnLinesOn = False
> res_at_gsnSpreadColors = True
> res_at_gsnAddCyclic = False
> res_at_gsnFrame = False
> res_at_gsnDraw = False
>
> resvctr = True
>
> resvctr_at_vcRefMagnitudeF = 4.0
> resvctr_at_vcRefLengthF = 0.045
> resvctr_at_vcRefAnnoOrthogonalPosF = -1.0
> resvctr_at_vcRefAnnoArrowLineColor = "black"
> resvctr_at_vcRefAnnoArrowUseVecColor = False
>
> resvctr_at_vcGlyphStyle = "CurlyVector"
> resvctr_at_vcLineArrowColor = "red"
> resvctr_at_vcLineArrowThicknessF = 2.0
> resvctr_at_vcVectorDrawOrder = "PostDraw"
> resvctr_at_vcMinDistanceF = 0.05
>
> ;############################
>
> plot = gsn_csm_contour_map(wks,speed,res)
>
> ;############################
> ; Contour
> ;############################
>
> ;cnres = True
> ;cnres_at_tfDoNDCOverlay = True ; don't transform
> ;cnres_at_cnInfoLabelOn = False ; turn off info label
> ;cnres_at_cnLineLabelsOn = True ; turn off line labels
> ;cnres_at_tiMainString = "Contour on Contour: Native Grid" ;
> title
> ;cnres_at_gsnDraw = False ; don't draw yet
> ;cnres_at_gsnFrame = False ; don't advance
> frame yet
>
> ;############################
>
> ;plotcn = gsn_contour(wks,vpt,cnres)
> ;overlay(plot,plotcn)
>
> ;############################
> ; Plot marker
> ;############################
>
> lon = -101.24
> lat = 38.87
> eps = 1e-3 ; or some small value
>
> polyres = True
> polyres_at_gsMarkerIndex = 16
> polyres_at_gsMarkerSizeF = 7.0
> polyres_at_gsMarkerColor = "black"
> draw(plot)
> gsn_polymarker(wks,plot,lon,lat,polyres)
>
> ;############################
> ; lat/lon Grid
> ;############################
>
> ;gridres = True
> ;gridres_at_gsMarkerIndex = 2
> ;gridres_at_gsMarkerSizeF = 10.0
> ;gridres_at_gsMarkerColor = "white"
> ;gsn_polymarker(wks,plot,ndtooned(lon2d),ndtooned(lat2d),gridres)
>
> ;############################
> ; Text Resources
> ;############################
>
> ;textres = True
> ;textres_at_txFontHeightF = 0.007 ; May need to change this
> ;textres_at_txFontColor = "black"
>
> ;############################
> ; Grid numbers
> ;############################
>
> ;nlat = dimsizes(lat2d(:,0)) ; Get dimension sizes
> ;nlon = dimsizes(lon2d(0,:)) ; of the lat/lon dimensions.
>
> ;do i=0,nlat-1
> ; do j=0,nlon-1
> ; text_string = (i+1)+","+(j+1) ; "1,1", "1,2", etc.
> ; gsn_text(wks,plot,text_string,lon2d(i,j),lat2d(i,j),textres)
> ; if( (lat2d(i,j)-eps).le.lat.and.lat.le.(lat2d(i,j)+eps).and.\
> ; (lon2d(i,j)-eps).le.lon.and.lon.le.(lon2d(i,j)+eps)) then
> ; vpt_text = ndtooned(vpt) + ""
> ; gsn_text(wks,plot,vpt_text,lon2d(i,j),lat2d(i,j),textres)
> ; end if
> ; end do
> ;end do
>
> vctrplot = gsn_csm_vector(wks,upt,vpt,resvctr)
> overlay(plot,vctrplot)
> draw(plot)
> gsn_polymarker(wks,plot,lon,lat,polyres)
>
> frame(wks)
>
> end
>
> --
> Jamie Ryan Lahowetz
> University of Nebraska - Lincoln
> Graduate Student - Geosciences
> 402.304.0766
> jlahowe2_at_bigred.unl.edu <mailto:jlahowe2_at_bigred.unl.edu>
>
>
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-- 
--------------------------------------------------------------
Adam Phillips			             asphilli_at_ucar.edu
National Center for Atmospheric Research   tel: (303) 497-1726
ESSL/CGD/CAS                               fax: (303) 497-1333
P.O. Box 3000				
Boulder, CO 80307-3000	  http://www.cgd.ucar.edu/cas/asphilli
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