Re: How to specify data coordinates in wrf_contour

Hi Gökhan,

wrf_contour simply draws the contours, with no map projection. wrf_map_overlays is what takes the contours and overlays them on a map.

If you really are only interested in wrf_contour and want to specify the data coordinates, then you need to read XLAT and XLONG off the file (I'm assuming you are plotting lat/lon data), and then set the special sfXArray and sfYArray resources.

Here's a working script that you can try, using the HGT variable on a wrf output file.

Try it both with and without the sfX/YArray settings, to see what happens to the plot. The "trGridType" setting is necessary in order to get tickmarks. If you were putting this over a map (via wrf_map_overlays), then you wouldn't need trGridType:

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/wrf/WRFUserARW.ncl"

begin
  a = addfile("wrfout.nc","r")
  hgt = wrf_user_getvar(a,"HGT",0)

  wks = gsn_open_wks("x11","mapgrid")

  res = True
  res@sfXArray = wrf_user_getvar(a,"XLONG",0)
  res@sfYArray = wrf_user_getvar(a,"XLAT",0)
  res@trGridType = "TriangularMesh"

  plot = wrf_contour(a,wks,hgt,res)

  draw(plot)
  frame(wks)

end

On Feb 27, 2014, at 5:43 AM, Gökhan Sever <gokhansever@gmail.com> wrote:

> Hello,
>
> Is there a way to specify X,Y coordinates of data surface within wrf_contour? [https://www.ncl.ucar.edu/Document/Functions/WRF_arw/wrf_contour.shtml]
>
> Similar to how is done in matplotlib's contour function [http://matplotlib.org/api/pyplot_api.html#matplotlib.pyplot.contour]
>
> Thanks.
>
>
> --
> Gökhan
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Received on Thu Feb 27 10:04:34 2014