[Mne_analysis] problem with plotting the positions of a selection of magnetometers

[Rasha Hyder]

Dear list,
I'm  having problems with plotting the positions of a selection of left
magnetometers. In the following I describe what I'm doing in steps to make
it easier to follow up with me (my apologies in advance if you find it too
long):

1. I selected the: 'Left-temporal', 'Left-parietal' and 'Left-frontal'
magnetometers:


*evoked = mne.read_evokeds()*


*left_chs= mne.read_selection(name= ['Left-temporal', 'Left-parietal',
                                    'Left-frontal'], info= evoked.info
<http://evoked.info>)my_evo= evoked.pick_types(meg='mag', selection=
left_chs)*

2. Then I tried to get the layout of only selected magnetometers using:

*pos = mne.channels.find_layout(my_evo.info <http://my_evo.info>)*

but this returned the layout of all 102 magnetometers although the
documentations says it chooses a layout based on the channels in the info
‘chs’ field!

To overcome this issue I had to use this:

*pos = mne.channels.find_layout(my_evo.info <http://my_evo.info>, exclude=
excluded_chs)*

where excluded_chs contains all magnetometers which are not in my selected
list *(left_chs)*
This worked and I checked the names of channels in *pos.names.*

3. when I tried to plot the positions of the selected sensors using:

*pos.plot() * and *mne.viz.plot_layout(pos) *

the plots showed the positions of the sensors spanning the whole head
scheme (please see attached figure_1).

4. I had the same problem also when plotting the topography of my own
defined evoked object *my_evo *(attached as figure_2):



*my_evo.plot_topomap()*
I would appreciate any suggestion to solve this problem.

Best regards
Rasha
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