[Mne_analysis] mne.create_info: Differences in info[ 'dig'] and info['chs']

[Gladia Hotan]

        External Email - Use Caution        

Hi,

I'm experimenting with creating info for a built-in montage:

montage = mne.channels.read_montage(kind='biosemi128')
fake_info = mne.create_info(ch_names=montage.ch_names, sfreq=250,
ch_types='eeg', montage=montage)

However, in the created info object, there are some differences between
info['chs'] and info['dig']:

   - There are 3 more channels in 'dig' than in 'chs'
   - The channel kinds are different in 'dig' than in 'chs'. For 'dig', the
   first 3 channels have kind '1' and the rest have kind '3'. For 'chs', the
   channels all have kind '2', and are identified as EEG channels by
   mne.io.pick.channel_type.
   - The coordinates in info['dig'][ind]['r'] don't match the coordinates
   in info['chs'][ind]['loc'][0:3].

Could someone explain why the channels kinds and locations don't match in
'chs' and 'dig'?

Thanks and Best,
Gladia
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