[pyngl-talk] Problems with plotting in Jupyter notebook cells

[Danielle Touma]

Hi Karin,

I am a new user of PyNGL (though a long-time user of NCL), and I really
appreciate how straightforward you have made the transition! Well done.

This may not be helpful to solve Mark's problem, but I would like to add
that I have a similar issue with using Ngl.end() in the python command
line. If I don't run Ngl.end() then my pdf does not complete the plotting
(even though I run Ngl.frame(wks) ) and I am unable to open the pdf. If I
do run Ngl.end(), the plotting works and I am able to open the pdf.
However, I have to exit python and reopen it so that I can open a new
workstation. It seems that the Ngl.end() command causes a disconnect from
the plotting/graphics for the session.

It might be something to do with the computing environment we are working
on, since I tend to have some issues with Casper (UCAR) and graphics
(XQuartz) in general.

Does this help you understand the issue more? If so, do you have any ideas
how to overcome this?

Best,
Danielle




On Tue, Jul 9, 2019 at 11:56 AM Karin Meier-Fleischer via pyngl-talk <
pyngl-talk at ucar.edu> wrote:

> I'm not able to reproduce the error, I was able to rerun it without
> restarting the kernel. Maybe it would be a good idea to delete those lines
> which are not needed like import of modules you are not using. Start with a
> short clean script and use more code cells. If you want to display the plot
> inline you can produce a PNG file, see attached notebook.
>
> -Karin
>
> Am 09.07.19 um 19:18 schrieb Mark England:
>
> Hi Karin,
>
> Attached. It is very simple and doesn’t need any data (just map plotting).
> If you run it once, it should work, however if you rerun the plotting cell
> (perhaps try to change the latitude or something) it will give you that
> error.
>
> Mark
>
>
> On 9 Jul 2019, at 10:02, Karin Meier-Fleischer <meier-fleischer at dkrz.de>
> wrote:
>
> Hi Mark,
>
> sometimes I have similar problems using notebook and PyNGL running with
> the same preconditions and have to restart the kernel. I don’t know if it
> is caused by PyNGL because I get other error messages. Is it possible to
> send the .ipynb file with test data to try to reproduce your errors?
>
> -Karin
>
> Am 09.07.2019 um 18:52 schrieb Mark England via pyngl-talk <
> pyngl-talk at ucar.edu>:
>
> Hi there,
>
> I am trying to transition to using PyNGL (using Jupiter Notebook, Python
> v3.7.3) on my Mac (Mojave 10.14.5).
> I am just trying to create simple plots (code below, mostly taken from the
> examples online. When I run the script first, it works fine and the pdf is
> created exactly as advertised. All the relevant modules are loaded.
> However if I re-run the plotting section of code in the Notebook, I get
> this error:
>
> fatal:["Error.c":406]:ErrorInitialize:Only one instance of ErrorClass is
> supported
> fatal:Unable to initialize layer-Can't Create
> fatal:Error Creating ErrorClass object
> fatal:Unable to initialize layer-Can't Create
> fatal:Unable to initialize layer-Can't Create
> fatal:_NhlCreate:Unable to access "default" App object
> fatal:_NhlCreate:Invalid Parent id #-4
> fatal:NhlGetValues:PID #-4 is invalid
> fatal:PID #-4 can't be found in NhlSetValues
> warning:maximize_plots: Invalid workstation. No plot maximization can take
> place.
> fatal:NhlDraw: Invalid Layer Id: -4
> fatal:Unable to update Workstation with PID#-4
> fatal:Unable to clear Workstation with PID#-4
> fatal:NhlDraw: Invalid Layer Id: -4
> fatal:Unable to update Workstation with PID#-4
> fatal:Unable to clear Workstation with PID#-4
> fatal:Unable to Destroy (Bad PID#0)
>
> I can only get the figure again, if, in the Kernel menu, I ‘restart and
> run all’. It seems to be a problem with the graphics? I have xQuartz
> installed. From a similar topic I found online, they removed Ngl.end() at
> the end, however that doesn’t work for me.
>
> Thanks,
>
> Mark
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>
>
>
> Mark England, PhD.
> Columbia University,
> *Bakhmeteff Research Fellow in Fluid Mechanics, *
> Email: mre2126 at columbia.edu <mre2126 at columba.edu>, markengland20 at gmail.com
> Website: markrossengland.com
>
>
> --
> Dipl. Geophys. Karin Meier-Fleischer
> Visualization, NCL, CDO, PyNGL
> Application Support
>
> Deutsches Klimarechenzentrum GmbH (DKRZ)
> Bundesstrasse 45a - D20146 Hamburg - Germany
>
> Phone:    +49 (0)40 460094 126
> Fax:      +49 (0)40 460094 270
> E-Mail:   meier-fleischer at dkrz.de
> URL:      www.dkrz.de
>
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>
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-- 
*Danielle Touma*
Postdoctoral Scholar
Bren School of Environmental Science & Management
University of California, Santa Barbara
touma at ucsb.edu
(919) 449-6377
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