[Eeglablist] Creating new coordinates following bipolar re-referencing

[Knut-André Skaug]

Hello,

I struggle with understanding how to transform cartesian coordinates to spherical and polar coordinates following the rules used in EEGLAB.

So far, I estimate the points of the bipolar references in cartesian space successfully, however when I try to use either:
'cart2sph.m.' or 'sph2cart.m' the output does not match the X, Y, Z variables in the chanlocs structure. In fact, only the radius matches the number.

Do you have functions allowing me to transform from cartesian coordinates to spherical and polar coordinates?

Any help is greatly appreciated.

I am making the bipolar montage called 'banana' - if you would like to have the script to perform this re-referencing, I am happy to share.

Some benefits to this bipolar reference scheme include more precise metrics aiming to show asymmetric spatial distributions, like left vs right hand EEG related activity.

[cid:image001.png at 01D9DCBE.80F07700]
Figure. Black dots show the location of the initial position of the electrodes as they were recorded. Green dots show the location of the bipolar re-referenced electrodes.

Kind regards
Knut Skaug
PhD Cognitive Neuroscience