Creates a contour plot from ARW WRF model output.
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl" ; These two libraries are automatically load "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl" ; loaded from NCL V6.4.0 onward. ; No need for user to explicitly load. function wrf_contour ( nc_file : file, wks : graphic, data [*][*] : numeric, res : logical ) return_val  : graphic
Reference to an input netCDF file opened with addfile.wks
A two-dimensional array to be contoured.res
A variable containing an optional list of plot resources, attached as attributes. See description section below for more information.
A scalar id of the plot created is returned.
This function creates a contour plot (but does not draw it). To draw the plot, see the example below.
If data has a _FillValue attribute, this value will be used as a missing value.
If data has a "description" attribute, this value will be used in the plot title.
This function recognizes some special resources that can be attached as attributes to res:
- ContourParameters - this resource can either be a scalar
that represents the contour level spacing, or it can be an array of
three elements that represent the minimum level, the maximum level,
and the level spacing. This resource is not recognized by
any of the gsn_xxxx plotting routines.
- gsnContourZeroLineThicknessF - sets the thickness of the
zero contour line. The default for this routine is 2.0 (when using any
of the gsn_xxx routines, the default is 1.0)
- gsnContourNegLineDashPattern - sets the line style of the
zero contour line. The default for this routine is 1, which is a
dashed line (see
the dash pattern table for more options). When using any of the
gsn_xxx routines, the default is 0 (a solid line).
- FieldTitle - This becomes the main title of the contour
plot. If not set, then the "description" attribute of the data
variable will be used, if available.
This also becomes part of the "information label" on the contour plot.
- SubFieldTitle - if set, this will be appended to the
FieldTitle title with a space between the two.
- UnitLabel - if set, this will be appended to the existing
FieldTitle title in parentheses. If not set, the "units" attribute of
the data_u variable will be used, if available.
- PlotLevelID - if set, this will be appended to the existing
FieldTitle title with an " at " between the two. If not set, the
"PlotLevelID" attribute of the data_u variable will be used, if
- NoHeaderFooter - Turn off all the extra titles. This
is useful if you need to panel the plot later.
The final main title could look something like "FieldTitle SubFieldTitle (UnitLabel) at PlotLevelID".
To make the labelbar vertical instead of horizontal, set these two resources:
res@lbOrientation = "vertical" res@pmLabelBarSide = "right"
wrf_contour is part of a library of functions and procedures in WRFUserARW.ncl written to help users plot ARW WRF model data.
WRF-related questions should be sent to email@example.com.
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl" load "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl" a = addfile("wrfout_d01_2000-01-24_12:00:00.nc","r") wks = gsn_open_wks("x11","test") ter = wrf_user_getvar(a,"HGT",0) ; Get terrain height for time 0 res = True res@cnFillOn = True res@gsnDraw = True ; Forces the plot to be drawn res@gsnFrame = True ; Frame advance contour = wrf_contour(a,wks,ter,res)You can see some other example scripts and their resultant images at: