[pyngl-talk] Ngl.contour problem, with masked array python 3

[Fearon, Dr. Matthew, Contractor, Code 7533]

Hi,

I was able to solve this error. Since ERA5 is global data, I needed to set
Ngl.add_cyclic for the data and the longitudes so mapping was correct. I
guess the key error was "contour_wrap": 

 

SystemError: <built-in function contour_wrap> returned NULL without setting
an error

 

Matt

 

 

From: pyngl-talk [mailto:pyngl-talk-bounces at ucar.edu] On Behalf Of Fearon,
Dr. Matthew, Contractor, Code 7533 via pyngl-talk
Sent: Saturday, July 20, 2019 1:02 PM
To: pyngl-talk at ucar.edu
Subject: [pyngl-talk] Ngl.contour problem, with masked array python 3

 

Hi,

I'm reading in ERA5 netcdf (e.g., for MSLP) with Nio and trying to plot with
Ngl.contour. I've done this hundreds of times with Python 2.7 (Nio,Ngl), but
now with my new Python 3 version, I'm getting the following error, which I
don't understand. It appears a masked_array is a problem? I probably missed
something obvious.

 

Thanks for the help,

Matt

 

 

Error:

NumPy arrays must be of type int, int32, float, float0, float32, or float64.

Traceback (most recent call last):

  File "./mapice.py", line 324, in <module>

    main()

  File "./mapice.py", line 320, in main

 
contour(band1,band2,band3,reds,blues,greens,xlat,xlon,ny,nx,mname,eslp,elat,
elon)

  File "./mapice.py", line 166, in contour

    contour_plot                     = Ngl.contour(wks,eice,clres)

  File
"/users/fearon/software/anaconda3/envs/pyn_env3/lib/python3.7/site-packages/
ngl/__init__.py", line 2830, in contour

    rlist2,rlist3,pvoid())

SystemError: <built-in function contour_wrap> returned NULL without setting
an error

 

 

Code snippet

       erasfc   = Nio.open_file(src_path+'/'+filelist[it]+'_sfc.nc',"r")

        if (it == 0):

            elat   = erasfc.variables['latitude'][:]

            elon   = erasfc.variables['longitude'][:]

 

        etmp = erasfc.variables['msl']

        eslp = (etmp[0,:,:]*etmp.scale_factor + etmp.add_offset) / 100.

        print (etmp.scale_factor)

[0.22592911]]

        print (etmp.add_offset)

[99425.54328544]

        print (type(eslp))

<class 'numpy.ma.core.MaskedArray'>

        print (eslp)

[[1009.1622356675263 1009.1622356675263 1009.1622356675263 ...

  1009.1622356675263 1009.1622356675263 1009.1622356675263]

[1009.5146850823248 1009.5146850823248 1009.5146850823248 ...

  1009.5146850823248 1009.5146850823248 1009.5146850823248]

[1009.8445415859185 1009.8445415859185 1009.8445415859185 ...

  1009.8445415859185 1009.8445415859185 1009.8445415859185]

...

[1013.2334782666748 1013.2447747222774 1013.2538118867593 ...

  1013.2018481909877 1013.2108853554698 1013.2244411021928]

[1012.5963581706925 1012.5986174618131 1012.6031360440542 ...

  1012.5805431328491 1012.5873210062106 1012.5918395884515]

[1012.0428318461692 1012.0428318461692 1012.0428318461692 ...

  1012.0428318461692 1012.0428318461692 1012.0428318461692]

 

    #Line contour settings

    clres = Ngl.Resources()

    clres.nglFrame                   = False

    clres.nglDraw                    = False

    clres.sfXArray                   = elon

    clres.sfYArray                   = elat

 

    clres.cnFillOn                   = False

    clres.cnFillDrawOrder            = "PreDraw"

    clres.cnLinesOn                  = True

    clres.cnLineColor                = "red"

    clres.cnLineThicknessF           = 5

    clres.cnLineLabelsOn             = False

    clres.cnLineLabelFontHeightF     = 0.010

    clres.cnLineLabelPerimOn         = False

    clres.cnLineLabelBackgroundColor = -1

    clres.cnInfoLabelOn              = False

#    clres.cnLevelSelectionMode       = "ExplicitLevels"

#    clres.cnLevels                   = [0.15]

#    clres.cnMinLevelValF             = 957

#    clres.cnMaxLevelValF             = 1002

#    clres.cnLevelSpacingF            = 2

#    clres.cnLineLabelInterval        = 1

    contour_plot                     = Ngl.contour(wks,eice,clres)

 

    Ngl.overlay(map_plot,contour_plot)]

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