why is there a random line extending outside plot boundaries?

When I plot the required data, there is a vertical line, which doesn't correspond to any values from input data and extends outside the plot boundaries (which I guess suggests it isn't an issue with the data itself). This did not happen in past versions of MATLAB but has persisted since updating to R2026a.

The code used is:

figure;
plot(TzedakisEtAl2018_FinalD18O_d13CStack.StackAge,TzedakisEtAl2018_FinalD18O_d13CStack.StackD18O___);

The x and y input data are from Columns 2 and 4 of Sheet 7 of the attached file, respectively.

[dpb]

Is this repeatable if you restart MATLAB or just a one-time aberration? If it is repeatable, post a minimal working example that reproduces the symptoms on your system so it can be seen if that can be reproduced since your supposition that it isn't actually coming from the data itself seems to be confirmed by @Star Strider here.

You could see if findall can uncover a spurious graphics object in the figure. If all else fails, this is then probably a candidate for a support ticket to see if MathWorks can reproduce the issue; if not it is likely a graphics driver issue of some sort.

[Sam Chak]

Hi @Kimberley

About 2½ years ago, a user experienced a similar issue, and @Adam Danz diagnosed it as possibly being related to a bug in the OpenGL renderer. For details, please refer to this thread:

https://www.mathworks.com/matlabcentral/answers/2112061-why-does-my-plot-line-appear-outside-the-axes

You may also want to check the output returned by rendererinfo() for troubleshooting purposes.

ax = gca(); 
r = rendererinfo(ax)
r.Details

[Star Strider]

If I remember correctly, MATLAB now uses the WebGL renderer, and has at least since R2025a.

rendererinfo

ans = struct with fields:
    GraphicsRenderer: 'WebGL'
              Vendor: 'Google Inc. (Google)'
             Version: 'WebGL 2.0 (OpenGL ES 3.0 Chromium)'
      RendererDevice: 'ANGLE (Google, Vulkan 1.3.0 (SwiftShader Device (Subzero) (0x0000C0DE)), SwiftShader driver)'
             Details: [1×1 struct]

.

Answer 1

[Star Strider]

figure
imshow(imread('Screenshot 202... 19.22.50.png'))

T1 = readtable('Tzedakis et al 2018.xlsx', Sheet=7, VariableNamingRule='preserve')

T1 = 1582×4 table
    Stack depth    Stack age    Stack d13C (‰)    Stack d18O (‰)
    ___________    _________    ______________    ______________

       48.22           108          -1.62             -4.67     
       48.25        108.02           -1.4              -4.8     
        48.3        108.04          -1.53             -4.83     
       48.34        108.05           -1.5             -4.82     
       48.37        108.07          -1.52             -4.72     
       48.41        108.09          -1.62             -4.58     
       48.46        108.11          -1.62              -4.6     
       48.55        108.16          -1.63             -4.55     
       48.61        108.18          -1.61             -4.82     
        48.7        108.21          -1.64             -4.53     
       48.85        108.32          -1.64             -4.63     
       48.96        108.44          -1.58             -4.52     
       49.02        108.54          -1.49              -4.4     
       49.06        108.62          -1.53             -4.48     
       49.09         108.7          -1.45             -4.58     
       49.11        108.73          -1.36             -4.31     

VN = T1.Properties.VariableNames

VN = 1×4 cell array
    {'Stack depth'}    {'Stack age'}    {'Stack d13C (‰)'}    {'Stack d18O (‰)'}

x = T1.(2);
y = T1.(4);

figure
plot(x, y)
% grid
xlabel(VN{2})
ylabel(VN{4})

It's not clear to me how you read the file, since only the plot call is presented. I'm not certain what could have caused the vertical line.

I cannot reproduce that error in R2026a using the provided data.

.