Date: Tue Feb 09 2010 - 18:26:58 MST
Dear Dave, Mary & others
ACE!! "vcMapDirection = False" works.
I've attached two plots that show the difference of setting vcMapDirection to be false or not.
Many thanks!!
Eunpa
__________________________________________________
Eun-Pa Lim; CAWCR
GPO Box 1289K, Melbourne 3001, VIC, AUSTRALIA
Phone +61 3 9669 4636; Fax +61 3 9669 4660 ; http://www.bom.gov.au/bmrc/
-----Original Message-----
From: David Brown [mailto:dbrown@ucar.edu]
Sent: Wednesday, 10 February 2010 04:01
To: Eun-Pa Lim
Cc: 'ncl-talk@ucar.edu'
Subject: Re: Question: Vectors over a map [SEC=UNCLASSIFIED]
Hi Eunpa,
Try setting vcMapDirection
(http://www.ncl.ucar.edu/Document/Graphics/Resources/vc.shtml#vcMapDirection
)
to False.
-dave
On Feb 8, 2010, at 9:59 PM, Eun-Pa Lim wrote:
>
> Hi,
>
> I am trying to draw wind vectors on a map.
>
> My first try was using gsn_csm_vector_map_ce.
>
> With a dummy data set that contains udata = 1 and vdata = 1 over
> regular grids of 73 lat x 144 lon (the same as NCEP2), I notice that
> the vector angle changes from 45 degree over the tropics to 0 degree
> at the pole (due to the longitudinal distance narrows down as the
> latitude increases).
>
> So I used gsn_csm_vector with
> res@vfXCStartV = 60.0
> res@vfXCEndV = 180.0
> res@vfYCStartV = -90
> res@vfYCEndV = 90
>
> And it solved my problem of vector angle (now I've got 45 degree
> angled vectors everywhere), but I can't overlay it with a map.
>
> Is there any way that I can draw vector plots with a map without
> having vector angles sensitive to latitude change?
>
> Many thanks,
>
> Eunpa
>
> __________________________________________________
>
> Eun-Pa Lim; CAWCR
> GPO Box 1289K, Melbourne 3001, VIC, AUSTRALIA Phone +61 3 9669 4636;
> Fax +61 3 9669 4660 ; http://www.bom.gov.au/bmrc/
>
>
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