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

[Arnaud Delorme]

Dear Khaled,

EGI location files can be read using the readegilocs and the files are stored in the "sample_locs" subfolder of the EEGLAB distribution. When you provide an EEGLAB dataset, the function will automatically look up a default file for your montage.

Best,

A. Delorme

On 28 Dec 2012, at 02:26, Khaled Al-Kamha wrote:

> Dear Tarik,
> 
> I think what happened is there is two versions of my question, i'll try to avoid that.
> 
> The eeglab reads the locations if the labels known via "Look up locs" button, and the dataset that i'm working in offer that http://www.physionet.org/pn4/eegmmidb/, 
> i just have to make sure that the labels named correctly, for example "C3" instead of "C3.." and the "Look up locs" works perfectly.
> 
> Thank you for your explanations, i don't have time now for understanding EGI location files, but i will find it and i'll be sure to post the file to the eeglab locations page soon.
> 
> I'm not using any egi system and 'm not an expert in this field.
> 
> Best,
> Khaled
>  
> 
> On Thu, Dec 27, 2012 at 10:17 PM, Tarik S Bel-Bahar <tarikbelbahar at gmail.com> wrote:
> 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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