[ncl-talk] Fwd: problem using ShadeGtContour function

[Rashed Mahmood]

Hi Adam,
Thanks, it works perfect!

On Tue, Apr 14, 2015 at 10:24 AM, Adam Phillips <asphilli at ucar.edu> wrote:

> Hi Rashed,
> If I understand the documentation correctly, one cannot pattern fill when
> cnFillMode = "CellFill" (or "RasterFill"). That is why you are getting
> black boxes.
>
> A couple of weeks ago Dave Brown sent a reply to a ncl-talk query of Frank Kreienkamp
> who was asking a similar type of question. From Dave's reply:
>
> A quirk, or perhaps a feature, of the AreaFill method is that the cells
> immediately adjoining an area of missing values are also treated as
> missing. In your example plot this reduces the stippled area to a fraction
> of what one might reasonably suppose it should be. One way to work around
> this is to eliminate the missing values. The idea is to set the missing
> values to a value outside the good value range, to a value that creates a
> plausible gradient from the nearest good value. Then set up the levels and
> level colors such that the formerly missing values will be drawn as a
> transparent color.
>
>
> Dave's suggestion is a good way to proceed with your issue. I have
> attached a modified version of your script, along with two .gif images. The
> first image shows the significant grid boxes (colored black) and the gray
> stippling overlaid on one another. With some testing one should be able to
> get gray stippling on each black grid box. The second image shows your plot
> with the stippling applied.
>
> Note that I modified your script to no longer use ShadeGtContour to give
> complete direct control of the stippling resources. It took some trial and
> error with setting the _FillValue attribute, along with the cnFillScaleF
> and cnFillDotSizeF resources (lines 69-72). You will likely have to modify
> those settings if your stippling field changes. I commented out lines 64-66
> and 74-77 as those were used to create the (trial and error) plot #1.
>
> Hope that helps.. If your have any further questions please respond to the
> ncl-talk email list.
> Adam
>
>
> On Mon, Apr 13, 2015 at 9:25 PM, Rashed Mahmood <rashidcomsis at gmail.com>
> wrote:
>
>>
>> Hi all,
>> Sorry if this message is repeated, last message was bounced back perhaps
>> because of the size of attached files, Below is my question.
>>
>>
>> I have been trying to use "ShadeGtContour" to get the stiplling pattern
>> on top of a map plot.
>> However the points do not appear on the plot, perhaps because these data
>> points are very few and sparse. Please see the top plot in attached figure.
>>
>> I could plot the points on the same map plot using "CellFill" resource,
>> but I would like them to appear as dots rather than filled boxes. See the
>> bottom plot in attached figure.
>>
>> The script and the two input files are attached that can used to produce
>> the problem.
>> Can anyone give some suggestions on how to get stiplling pattern when the
>> data points are few and sparse.
>>
>> Thanks
>> Rashed
>>
>>
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>
>
> --
> Adam Phillips
> Associate Scientist,  Climate and Global Dynamics Laboratory, NCAR
> www.cgd.ucar.edu/staff/asphilli/   303-497-1726
>
> <http://www.cgd.ucar.edu/staff/asphilli>
>
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