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

[Buzan, Jonathan]

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<mailto: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<mailto: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<mailto: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<mailto: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<mailto: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<http://tst_diff.nc/>><Mask_TEST_Original.pdf><Mask_TEST_Bogus.pdf>_______________________________________________
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