[Eeglablist] Montage for BioSemi 64 cap

[Andreas Widmann]

Hi Andre,

 > However, when this is used as the locations,
> the electrode placement is off considerably, because it seems that the
> Biosemi angles are not standard ways of expressing the coordinates.
It is a constant nightmare that there is no real standard for spherical 
coordinates.

In EEGLAB sph_theta is longitude with 0 pointing towards nose, positive 
values for left hemisphere and negative values for right hemisphere. 
sph_phi is latitude with 0 on the equatorial plane and positive values 
towards vertex.

Thus,
sph_theta = C - 90 * sign(B)
and
sph_phi = -abs(B) + 90
should give you EEGLAB compatible spherical coordinates with B and C 
denoting the columns in the BioSemi Excel file.

Best,
Andreas
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