Hi Mary,
I think you left out one thing that is necessary for overlaying on
the LogLinPlot using "straight NCL": the data coordinate extents of the
LogLinPlot needs to match the actual data extents. The easy way to do this
is analogous to setting the viewport; just retrieve and set the
tr[X|Y][Min|Max]F resources:
getvalues contour
"vpXF" : vpx
"vpYF" : vpy
"vpWidthF" : vpw
"vpHeightF" : vph
"trXMinF" : xmin
"trXMaxF" : xmax
"trYMinF" : ymin
"trYMaxF" : ymax
end getvalues
;
; Create a loglin plot object.
;
loglin = create "LogLin" logLinPlotClass wks
"vpXF" : vpx
"vpYF" : vpy
"vpWidthF" : vpw
"vpHeightF" : vph
"trXMinF" : xmin
"trXMaxF" : xmax
"trYMinF" : ymin
"trYMaxF" : ymax
end create
Also a nitpick: I assume you mean in your example code to set the
data in the ScalarField, i.e:
dataid = create "data" scalarFieldClass defaultapp
"sfDataArray" : contour_data
"sfXArray" : xg
"sfYArray" : yg
end create
On Tue, 25 Jun 2002, Mary Haley wrote:
.....
>
> There's a good example of how to do this in frame 4 of the the NCL
> example "cn03n". To generate this example, type:
>
> ng4ex cn03n
>
> Then, edit the file and search for "logLinPlotClass", and you'll see
> how the overlay is done. Below is a similar example of how this might
> work.
>
> contour_data = (/some 2D array/)
> ;
> ; Open an X11 workstation.
> ;
> wks = create "x11" xWorkstationClass defaultapp end create
> ;
> ; Create a data object.
> ;
> dataid = create "data" scalarFieldClass defaultapp
> "sfXArray" : xg
> "sfYArray" : yg
> end create
> ;
> ; Create a contour plot object.
> ;
> contour = create "plot" contourPlotClass wks
> "cnScalarFieldData" : dataid
> end create
> ;
> ; Retrieve the viewport coordinates so we can use them to
> ; specify the exact same coordinates for the loglin plot.
> ;
> getvalues contour
> "vpXF" : vpx
> "vpYF" : vpy
> "vpWidthF" : vpw
> "vpHeightF" : vph
> end getvalues
> ;
> ; Create a loglin plot object.
> ;
> loglin = create "LogLin" logLinPlotClass wks
> "vpXF" : vpx
> "vpYF" : vpy
> "vpWidthF" : vpw
> "vpHeightF" : vph
> end create
> ;
> ; Overlay the contour plot on the loglin plot.
> ;
> overlay(loglin,contour)
> ;
> ; The loglin plot becomes the base plot that contains the
> ; contour plot, so to draw the contour plot, you must draw
> ; the loglin plot.
> ;
> draw(loglin)
> ;
> ; Advance the frame.
> ;
> frame(wks)
>
> >
> > When I try and use the gsn_contour routine and set the attributes, I
> > also get the correct cooridinate values plotted but no change in the plot.
> >
> >
> > Lou Wicker
> >
>
> This whole process is a little easier if you are using gsn_contour.
> You can set the special "gsn" resource "gsnYAxisIrregular2Linear" to
> True, and the creating/overlaying of the logLinPlotClass will take
> place behind the scenes.
>
> Your GSUN script might look something like this:
>
>
> contour_data = (/some 2D array/)
> wks = gsn_open_wks("x11","example") ; Open an X11 workstation.
>
> res = True
> res@sfXArray = xg
> res@sfYArray = yg
> res@gsnYAxisIrregular2Linear = True
>
> contour = gsn_contour(wks,contour_data,res) ; Draw plot and advance frame.
>
> --Mary
>
> >
> > ================================================
> > Dr. Louis J. Wicker
> > Research Scientist, National Severe Storms Lab
> > 1313 Halley Cir, Norman, OK 73069
> > E-mail: Louis.Wicker@nssl.noaa.gov
> > Phone: (405) 366-0416 / Fax: (405) 579-0808
> > Norman's Little River Zoo on SE 120th off Rt. 9:
> > Your zoo for life!
> > ===============================================
> _______________________________________________
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>
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