[Eeglablist] how to draw map figures using averaged data

Joseph Dien jdien07 at mac.com
Sun Aug 4 14:16:56 PDT 2013


I've run into a similar problem.  I've just reported the bug:

There is an incompatibility between pop_chanedit and readlocs.  If one, for example, reads a .loc file (with four columns corresponding to channel number, two coordinates, and the channel label) into pop_chanedit using the "read locations" button and accepts the auto detect choice and then saves the data using the "save (as .ced)" button, it produces a .ced file with 13 columns:


    'theta'
    'radius'
    'labels'
    'sph_theta'
    'sph_phi'
    'X'
    'Y'
    'Z'
    'datachan'
    'sph_radius'
    'type'
    'ref'
    'urchan'

readlocs, on the other hand, expects the following fields:

'channum'    
'labels'    
'theta'    
'radius'   
 'X'    
'Y'   
 'Z'   
 'sph_theta'   
 'sph_phi'    
'sph_radius'
'type'

Joe


On Apr 2, 2013, at 5:58 AM, Stephen Politzer-Ahles <politzerahless at gmail.com> wrote:

> Hi Jianrong,
> 
> I guess there's some problem with your channel location file, as this same code worked for me when I used one of my own files. But I can't tell what the issue is without seeing the file; can you send it to me?
> 
> If your data imported in EEGLAB already have channel locations, there are some other ways you could try getting this to work. The EEG.chanlocs structure has the information you need, so rather than reading the locations you can just put EEG.chanlocs in the spot where you currently have 'PE_loc.txt', like in this example:
> 
> data = mean( mean( EEG.data(:,100:150,:), 3 ), 2); % average across epochs and timepoints
> figure; topoplot( data, EEG.chanlocs, 'electrodes', 'labels' );
> 
> Or, you can use the pop-up menu at "Plot ERP map series". (As far as I know, this only allows you to plot single time points, not averages across time points; but right now I'm at a computer with an older version of EEGLAB on it, I'm not sure if this is changed in recent versions; and if you can make a plot using this menu, you can use 'eegh' to see the command and then you can adapt it).
> 
> Best,
> Steve
> 
> 
> On Tue, Apr 2, 2013 at 12:28 AM, Jianrong Jia <jianrongjia at hotmail.com> wrote:
> Hi Steve,
> I runed topoplot command like this:
> yyy=[1:1:64];
> topoplot(yyy,'PE_loc.txt','electrodes','labels') ;
> and recieved following error message:
> readlocs(): '' format assumed from file extension
> readlocs() warning: More columns in the input than expected.
>                     See >> help readlocs
> Undefined function or variable "eloc".
> Error in readlocs (line 458)
>    if isfield(eloc, 'sph_theta_besa')
> Error in topoplot (line 640)
>         [tmpeloc labels Th Rd indices] = readlocs( loc_file);
> The PE_loc.txt was exported by Edit-Channel locations-Save(Other types) of EEGLAB. I checked the PE_loc.txt and  be sure that it's channel corresponding to my data.
> Is anything wrong?
>  
> Best.
> Jianrong
> ------------------ Original ------------------
> From:  "Stephen Politzer-Ahles"<politzerahless at gmail.com>;
> Date:  Tue, Apr 2, 2013 03:51 AM
> To:  "Jianrong Jia"<jianrongjia at hotmail.com>;
> Cc:  "eeglablist"<eeglablist at sccn.ucsd.edu>;
> Subject:  Re: [Eeglablist] how to draw map figures using averaged data
> 
> Hello Jianrong,
> 
> Once you've imported the data into EEGLAB, you can use the topoplot() function to draw topographic maps of a particular time point, or an average over multiple timepoints.. See the topoplot() help information for more details and examples.
> 
> Best,
> Steve
> 
> 
> On Sat, Mar 30, 2013 at 11:08 AM, Jianrong Jia <jianrongjia at hotmail.com> wrote:
> Dear all
> I have a grand averaged data has been exported by Analyzer 2(Brain Products Corp.). It is only one second. How can i draw maps using this data.
> 
> Jianrong
>  
> 
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> 
> 
> -- 
> Stephen Politzer-Ahles
> University of Kansas
> Linguistics Department
> http://people.ku.edu/~sjpa/
> 
> 
> 
> -- 
> Stephen Politzer-Ahles
> University of Kansas
> Linguistics Department
> http://people.ku.edu/~sjpa/
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--------------------------------------------------------------------------------

Joseph Dien,
Senior Research Scientist
Maryland Neuroimaging Center
University of Maryland 

E-mail: jdien07 at mac.com
Phone: 202-297-8117
http://joedien.com














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