Re: can't plot vectors

Hi Vishali,

I see the problem. Your data is actually of type "short" and has
"scale" and "offset" attributes that you should apply to the data
before plotting it.

We have a special function for this, "short2flt".

http://www.ncl.ucar.edu/Document/Functions/Contributed/short2flt.shtml

Try replacing:

   u = a->uwnd(0,0,:,:)
   v = b->vwnd(0,0,:,:) ; Get u, v, time (1),level
(1000hpa),latitude(-90:90) and longitude(0:360) data.

with:

   u = short2flt(a->uwnd(0,0,:,:))
   v = short2flt(b->vwnd(0,0,:,:)) ; Get u, v, time (1),level
(1000hpa),latitude(-90:90) and longitude(0:360) data.

--Mary

On Jun 30, 2010, at 9:31 AM, Vishali P. wrote:

> Mary
>
> This is my script and data
>
> 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("/uwnd1998.nc","r")
> print(a)
> b = addfile("/vwnd1998.nc","r")
> ;************************************************
> ; read in zonal [u] and meridional [v] winds (July)
> ;************************************************
> u = a->uwnd(0,0,:,:)
> v = b->vwnd(0,0,:,:) ; Get u, v, time (1),level
> (1000hpa),latitude(-90:90) and longitude(0:360) data.
>
> speed = sqrt(u^2+v^2)
>
> printVarSummary(u)
> printVarSummary(v)
>
> ;************************************************
> ; create plot
> ;************************************************
> wks = gsn_open_wks("ps","vector") ; open a ps file
> gsn_define_colormap (wks,"BlAqGrYeOrRevi200") ; choose color map
>
> 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 = 0.00004 ; define length
> of vec ref
> vcres@vcGlyphStyle = "CurlyVector" ; turn on curly
> vectors
> vcres@vcMinDistanceF = 0.017
>
> ;************************************************
> ; Choose a subregion
> ;************************************************
> vcres@mpFillOn = False ; turn off gray
> fill
> vcres@mpOutlineBoundarySets = "National" ; turn on country
> boundaries
> vcres@mpGeophysicalLineColor = "Navy" ; color of cont.
> outlines
> vcres@mpGeophysicalLineThicknessF = 1.5 ; thickness of
> outlines
>
> vcres@mpMaxLatF = 0 ;maximum latitude
> vcres@mpMinLatF = -45 ;minimum latitude
> vcres@mpMaxLonF = 55 ;maximum longitude
> vcres@mpMinLonF = 5 ;minimum longitude
>
> vector = gsn_csm_vector_map_ce(wks,u,v,vcres)
> ;************************************************
> ; add time stamp to plot
> ;************************************************
> infoTimeStamp(wks,0.025,"uwnd.1998.nc") ; arguments are
> workstation
> ; size of text desired, and
> ; right string.
> frame (wks)
> end
>
>
> Thanks
>
> Vishali P.
>
>
>
> On Mon, Jun 28, 2010 at 11:19 PM, Mary Haley <haley@ucar.edu> wrote:
> Vishali,
>
> I don't think this is an NCL problem, but it would help if you could
> provide your script and data.
>
> --Mary
>
> On Jun 28, 2010, at 2:32 AM, Vishali P. wrote:
>
>> Adam,
>>
>> Thanks for help, I've tried to change those values , and I even
>> succeeded to cut, but the problem is that the vectors are going all
>> to the same direction. I've also tried to not make zoom of the map,
>> but there's no change on vectors direction (see "vector_2"). Is
>> there any other solution?
>>
>> vcres@vcRefMagnitudeF = 10.0 ; define vector
>> ref mag
>> vcres@vcRefLengthF = 0.00004 ; define
>> length of vec ref
>>
>>
>> Please help
>>
>> Vishali P
>>
>>
>>
>>
>> On Wed, Jun 23, 2010 at 2:48 PM, Adam Phillips <asphilli@ucar.edu>
>> wrote:
>> VP,
>> vcres@vcRefMagnitudeF = 10.0 ; define vector
>> ref mag
>> vcres@vcRefLengthF = 0.045 ; define length of
>> vec
>>
>> I believe the curly vectors are being drawn, but they are too long.
>> Try
>> adjusting the resources I pasted above downward.. At first guess I
>> would
>> cut them in half... Let us know if you still can't figure it out...
>> Adam
>>
>> > *Dear NCL users.
>> >
>> > I am using this script to plot the wind vectors using ncep/
>> reanalysis data
>> > 1998. I've tried to plot wind components, but in the plot they
>> aren't
>> > going
>> > the way that it should be. Something strange is happening.
>> >
>> >
>> > Any help is strongly appreciated
>> >
>> > Vp*
>> >
>> >
>> ___________________________________________________________________________________
>> >
>> > 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("/uwnd.1998.nc","r")
>> > print(a)
>> > b = addfile("/vwnd.1998.nc","r")
>> > ;************************************************
>> > ; read in zonal [u] and meridional [v] winds (July)
>> > ;************************************************
>> > u = a->uwnd(1,0,:,:)
>> > v = b->vwnd(1,0,:,:) ; Get u, v, time (1),level
>> > (1000hpa),latitude(-90:90)
>> > and longitude(0:360) data.
>> >
>> > speed = sqrt(u^2+v^2)
>> >
>> > printVarSummary(u)
>> > printVarSummary(v)
>> >
>> > ;************************************************
>> > ; create plot
>> > ;************************************************
>> > wks = gsn_open_wks("ps","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
>> >
>> > ;************************************************
>> > ; Choose a subregion ou fazer zoom
>> > ;************************************************
>> > vcres@mpFillOn = False ; turn off
>> gray fill
>> > vcres@mpOutlineBoundarySets = "National" ; turn on
>> country
>> > boundaries
>> > vcres@mpGeophysicalLineColor = "Navy" ; color of cont.
>> > outlines
>> > vcres@mpGeophysicalLineThicknessF = 1.5 ; thickness of
>> outlines
>> >
>> > vcres@mpMaxLatF = 0 ;maximum latitude
>> > vcres@mpMinLatF = -45 ;minimum latitude
>> > vcres@mpMaxLonF = 55 ;maximum longitude
>> > vcres@mpMinLonF = 5 ;minimum longitude
>> >
>> > vector = gsn_csm_vector_map_ce(wks,u,v,vcres)
>> > ;************************************************
>> > ; add time stamp to plot
>> > ;************************************************
>> > infoTimeStamp(wks,0.025,"uwnd.1998.nc") ; arguments are
>> workstation
>> > ; size of text
>> desired, and
>> > ; right string.
>> > frame (wks)
>> > end
>> > _______________________________________________
>> > ncl-talk mailing list
>> > List instructions, subscriber options, unsubscribe:
>> > http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>> >
>>
>>
>>
>> <vector_2.jpeg>_______________________________________________
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>
>
> <vector.jpeg>

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Received on Wed Jun 30 11:00:52 2010