[ncl-talk] Plot of constant values

[Alan Brammer]

It'll take someone with knowledge on the background plotting code to say
more, but I think you're running into an issue of trying to contour a
region over only ~4 data points.  Looks like AreaFill needs more than 4
data points to calculate the contours. There should probably be an error
check here.

If you change the cnFillMode  to CellFill or RasterFill then it'll plot as
expected.  Or expand your region to include more than 4 data points.

cnFillMode = "RasterFill"
cnRasterSmoothingOn = True

The combination of those two resources will produce contours that are very
similar to AreaFill.


~Alan

On Wed, Nov 12, 2014 at 8:46 AM, Raffaele Quarta <raffaele.quarta at linksmt.it
> wrote:

>  Ok, sorry if I got wrong since I called functions instead of resources.
> I'm trying to make a plot of NetCDF file, by using a tiling approach and
> making a subset of the data.
> Although I add the following two lines in my script, as you suggested, I
> can't obtain what I'd like to.
>
> --------------------------------
> res at cnConstFEnableFill = True   |
> res at cnConstFLabelOn = False     |
> --------------------------------
>
> Attached you will find:
>
> - file_input_crop.nc (NETCDF input file that I'm using)
> - tms_output.png (an example of output .PNG that I got)
> - tms_test.ncl (the script that I'm using for the plot)
>
> Looking at the output, I believe that NCL isn't able to get the constant
> value in the selected bounding area.
>
> Maybe I'm not using appropriately the resources.
>
> Thank you for the help
>
> Raffaele
>
> -----Original Message-----
> From: Alan Brammer [mailto:abrammer at albany.edu <abrammer at albany.edu>]
> Sent: Tue 11/11/2014 6:08 PM
> To: Raffaele Quarta
> Cc: ncl-talk at ucar.edu
> Subject: Re: [ncl-talk] Plot of constant values
>
> It'll help everyone solve this by describing how it is not working?  Also
> fyi these are resources not functions.
>
>
> This works exactly as expected for me in 6.2.0 and 6.2.1.
>
>
> x = new ( (/100,100/), float)
> x = 100
>
> wks = gsn_open_wks("X11","ConstFill_wks")
>
> res = True
> res at cnFillOn = True                 ;;;;  The contour needs to be filled
> to
> start with, for a constant value to be filled.
> res at cnConstFEnableFill = True
> res at cnConstFLabelOn = False
>
> plot = gsn_csm_contour(wks, x, res)
>
>
>
>
> Alan Brammer
>
>
>
> On Tue, Nov 11, 2014 at 11:29 AM, Raffaele Quarta <
> raffaele.quarta at linksmt.it> wrote:
>
> >  Hi,
> >
> > I'm using the 6.2.0 NCL version. Actually, I'm dealing with the problem
> to
> > plot an area with constant value.
> > I saw that starting from the version 6.2.0, the following function is
> able
> > to solve the problem.
> >
> > -------------------------
> > cnConstFEnableFill
> >
> > Available in version 6.2.0 and later.
> > If the boolean resource cnConstFEnableFill is set to True, then in most
> > cases, constant or near-constant fields will be rendered as a filled
> area,
> > rather than having the contoured area remain blank. By default, the
> > constant field informational text box will still appear; turn it off by
> > setting cnConstFLabelOn to False.
> >
> > In the future, cnConstFEnableFill will likely default to True, with
> > cnConstFLabelOn defaulting to False unless contour line drawing is
> enabled.
> >
> > Default: False
> > -----------------------
> >
> > I tried to use this solution but it seems not working. Maybe it a bug of
> > the software?
> > Can you suggest a different solution?
> >
> > Thank you very much.
> >
> > Raffaele
> >
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