[ncl-talk] Strange stippling behaviour when valid points are few and scattered apart

[Dennis Shea]

This was looked at offline.

Likely, there is a "bug of some kind." See Adam's response below. He also
provided a sample script
.


Adam Phillips provided the attached script.

Stay Healthy
==========

On Thu, Jul 2, 2020 at 12:57 PM Buzan, Jonathan via ncl-talk <
ncl-talk at mailman.ucar.edu> wrote:

> You need to delete _FillValue and set the number to some arbitrary value.
>
> -Jonathan
>
>
>
> On Jul 2, 2020, at 8:55 PM, Rashed Mahmood <rashidcomsis at gmail.com> wrote:
>
> I do not think that we should use 0 as missing value, please also see this
> page:
>
> http://www.ncl.ucar.edu/Document/Language/error_messages.shtml#ZeroMissingValue
> and no, setting _FillValue to some arbitrary number does not work.
>
> I am guessing that there may be a workaround for this, which I haven't
> found yet!
>
>
>
> On Wed, Jul 1, 2020 at 7:06 PM Buzan, Jonathan <jbuzan at purdue.edu> wrote:
>
>> I think it’s interpolating between the data.
>> Have you tried deleting the _FillValue and set it to 0 (or some arbitrary
>> number)?
>>
>> -Jonathan
>>
>>
>>
>>
>>
>> On Jul 1, 2020, at 6:25 PM, Rashed Mahmood <rashidcomsis at gmail.com>
>> wrote:
>>
>> Jonathan,
>> Please look at the if statement that was introduced just to play with it
>> a bit. Please have a look at the plot named *_Original.pdf. This is what
>> the question is about.
>>
>> Rashed
>>
>> On Wed, Jul 1, 2020 at 6:03 PM Buzan, Jonathan <jbuzan at purdue.edu> wrote:
>>
>>> Hi Rashed,
>>>
>>> Looking at your script, it looks like the stipple is doing exactly what
>>> you said it to do:
>>>
>>>       do n=0,20
>>>          sig({n},:) = 95.01
>>>       end do
>>>
>>>
>>> You set  resS at cnLevels             =(/ 95.,100. /)
>>>
>>> The {n} in sig({n},:) means to set the latitudes 0-20 to 95.01. And the
>>> stipple is greater than 95. But lower than 100. So it stippled from 0-20
>>> latitude.
>>>
>>> -Jonathan
>>>
>>>
>>>
>>>
>>> > On Jul 1, 2020, at 5:57 PM, Rashed Mahmood via ncl-talk <
>>> ncl-talk at mailman.ucar.edu> wrote:
>>> >
>>> > Hi NCL,
>>> >
>>> > I encountered strange stippling behaviour when valid data points are
>>> very few and are scattered apart from each other. At best I would expect no
>>> stippling overlaid on a filled map, however, it seems that NCL somehow
>>> covers the whole map with stippling.
>>> >
>>> > To explain this, I created a small example script (attached) which
>>> reads data from the attached file. To play with it a bit, I just added some
>>> "fake data" to see what happens. In the script we could set it using
>>> "add_bogus_data = True".
>>> > Attached are two plots after using original data and adding some fake
>>> data. I am not sure what is going on here, anyone? Ignore the file names!!
>>> >
>>> > Cheers
>>> > Rashed
>>> >
>>> > <funny_stiple.ncl><tst_diff.nc
>>> ><Mask_TEST_Original.pdf><Mask_TEST_Bogus.pdf>_______________________________________________
>>> > ncl-talk mailing list
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>>>
>>>
>>
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