Question: Vectors over a map [SEC=UNCLASSIFIED]

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/

_______________________________________________
ncl-talk mailing list
List instructions, subscriber options, unsubscribe:
http://mailman.ucar.edu/mailman/listinfo/ncl-talk
Received on Mon Feb 8 21:59:11 2010