open-discussion > Electrode editor coordinates
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Apr 25, 2019  05:04 AM | Erik Gommer
Electrode editor coordinates
Dear all,

I would like to use the BIS Electrode Editor to create electrode location files of grid-electrode to use in EEGlab for further processing. I exported the .mgrid files as .txt files which resulted in a file with locationx, locationy and locationz for each electrode.

Which coordinate system is used for these location files and what is the origin of the coordinate system?
Can these location files easily be transformed to EEGlab ready formats like .ced or .loc? 

Thanks in advance.

Erik Gommer
Apr 25, 2019  06:04 AM | Larry Olson - Emory University
RE: Electrode editor coordinates
Originally posted by Erik Gommer:
Dear all,

I would like to use the BIS Electrode Editor to create electrode location files of grid-electrode to use in EEGlab for further processing. I exported the .mgrid files as .txt files which resulted in a file with locationx, locationy and locationz for each electrode.

Which coordinate system is used for these location files and what is the origin of the coordinate system?
Can these location files easily be transformed to EEGlab ready formats like .ced or .loc? 

Thanks in advance.

Erik Gommer
I am not sure if this will be helpful to you- but maybe to someone! I attached a Word macro that converts BIS coordinates to Slicer coordinates (for a "centered" label file). We no longer use this. Currently our electrode visualization is done strictly with sEEG (no grids anymore) in Slicer with Masimo Narizanno's automated Contact Position Estimator. It is quite elegant, but (I know) off topic here. So, yes, it is possible to create a transformation rule. You must work with the BIS text file to do that. Whether or not your other programs can use it depends on whether they can read the modified text file. But is is also possible to create a beautiful labeling of contacts without BIS.