The following electrodes have overlapping positions, which causes problems during visualization

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1

  • MNE version: 0.22.0

  • operating system: Windows 11

    File “C:\Users\Colin\AppData\Roaming\Python\Python38\site-packages\mne\channels\layout.py”, line 726, in _auto_topomap_coords
    raise ValueError(‘The following electrodes have overlapping positions,’
    ValueError: The following electrodes have overlapping positions, which causes problems during visualization:
    MEG 0113, MEG 0112, MEG 0122, MEG 0123, MEG 0132, MEG 0133, MEG 0143, MEG 0142, MEG 0213, MEG 0212, MEG 0222, MEG 0223, MEG 0232, …,MEG 2642, MEG 2643
    I cant understand the reason about these error If you know how to fix this error I will very gratitude.And the function info parameter is that:

<Info | 13 non-empty values
 bads: []
 ch_names: MEG 0113, MEG 0112, MEG 0122, MEG 0123, MEG 0132, MEG 0133, MEG ...
 chs: 203 GRAD
 custom_ref_applied: False
 dev_head_t: MEG device -> head transform
 dig: 146 items (3 Cardinal, 4 HPI, 61 EEG, 78 Extra)
 file_id: 4 items (dict)
 highpass: 0.1 Hz
 hpi_meas: 1 item (list)
 hpi_results: 1 item (list)
 lowpass: 40.0 Hz
 meas_date: 2002-12-03 19:01:10 UTC
 meas_id: 4 items (dict)
 nchan: 203
 projs: []
 sfreq: 150.2 Hz
>
2

the error means that multiple electrodes have exactly the same position. Very likely this position is (0, 0, 0). The position of the channels is stored in info.chs[index_of_the_channel].pos

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3

Isn’t it weird that there only seem to be MEG channels, yet MNE complains about electrodes?

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4

It uses _auto_topomap_coords which is only used when there is no pre-programmed layout available. For most MEG devices, we have these pre-programmes layouts, so the error message assumes EEG.

But this could be a sign of something wrong: what MEG device is this? It looks like a MegIn device to me and for that, positions should just work. @dengzuxuan could you perhaps share more of your code and what exactly the data comes from and what you are trying to do with it?

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