[Eeglablist] 1. Re: Channel Location File (Stephen Politzer-Ahles)

[Tarik S Bel-Bahar]

Hi Khaled,

just a few quick thoughts that might help you...let us know of your
success. When you are done
please be sure to post your file to the eeglab locations page.

I think when it says .txt file, it means that EEGLAB can accept location
files that are in a text format.
That being said, I am sure the info within the text file has to be
formatted correctly. You can check
yourself by looking at the content of example channel location files.
Eeglab generally can recognize and import most of these file types.

The EGI document table basically lists labels (such as the 10-10 labels) in
the first column.
For example, on page 7, using a 128 channel Hydrocel EGI montage, the
closest to C3 is channel 36.
If you read the explanation, the arclength should be total estimated error
in distance between the
actual electrode and the ideal 10-10 label in question.

Just be careful because there are old and new(hydrocel) EGi location files.
In the past, what I did was within eeglab, I modified the labels for the
channels with the correct 10-10 labels
for an egi system. If you are indeed using a 64-channel net, then you need
to find the correct files
and 10-10 or 10-20 matches for that montage. If using EGI system, you can
contact egi support
if you don't find it by searching further on their ftp site. You should
have already found this
tech note there:
http://ueleeglabwiki.pbworks.com/f/200_ElectrodePositions.pdf

some other points: it's not clear if you are using an egi system, and
whether you actually have
a general locations file for the 64 net that you are using.

Good luck with your process!


On Thu, Dec 20, 2012 at 1:56 PM, Khaled Al-Kamha
<khaled.alkamha at gmail.com>wrote:

> Hi Steve,
>
> I'm working on EGGLAB, and as i see here ftp://sccn.ucsd.edu/pub/locfiles/ EEGLAB
> channel location formats are:
>
> ".loc" for polar coordinates
> ".xyz" for 3-d carthesian coordinates
> ".sph" for 3-d spherical coordinates
> ".txt" for all coordinates formats
>
> It seems i need the ".txt" file for further steps, but i didn't find it
> for my 10/10 standard and 64 channels.
> actually, i have kind of poor experience in this field and critical time
> for my graduation project, plus i didn't fully understand what the table
> means ftp://ftp.egi.com/pub/documentation/technotes/HydroCelGSN_10-20.pdf
> Any simple explanations, i appreciate it
>
> Thanks in advance
>
> On Wed, Dec 19, 2012 at 4:01 AM, <eeglablist-request at sccn.ucsd.edu> wrote:
>
>>  1. Re: Channel Location File (Stephen Politzer-Ahles)
>
>
>
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