[Mne_analysis] Displaying .stc data as discreet 'hexagons' of colour on the freesurfer-generated mesh

[acgt2 at cam.ac.uk]

Hi MNE mailing-list,

I am trying to display my .stc data (downsampled to 10242 sources) as
discreet 'hexagons' of colour on the freesurfer-generated mesh, with sharp
boundaries (ie no interpolation), between each hexagon. 

(I am not doing this colouring using any of the MNE visualisation tools,
instead rendering the mesh and colouring vertices/faces using openGL)

Unfortunately, although the 'data-bearing' vertices are at the centre of
'notional' tessellating hexagons, these hexagons are not exactly divisible
by faces (see attached - white is the actual mesh, black the 'notional'
hexagons, and 'D' represents the data bearing vertices present in the .stc
file). You can see that I have problems in the corners of each of the
'notional' hexagons, as the black and white lines don't match.

So a couple of questions:

I'm guessing that this was the reason to use smoothing/blurring in
MNE_analyse (chapter 8.3 of the manual) rather than simply having discreet
hexagonal patches, in as much that set at the right level, the resultant
colouring will always begin to approximate hexagons? Second, is this
mismatch between the notional hexagon and mesh faces true for all
resolutions (I'm pretty sure it is, but just want to check)? And lastly -
has anyone else wanted to display these discreet 'notional' hexagons and
thought of a work-around?

Thanks in advance for any thoughts,

Andy

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.nmr.mgh.harvard.edu/pipermail/mne_analysis/attachments/20131111/ac181e6b/attachment.html 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: colouring-test.jpg
Type: image/jpeg
Size: 131147 bytes
Desc: not available
Url : http://mail.nmr.mgh.harvard.edu/pipermail/mne_analysis/attachments/20131111/ac181e6b/attachment.jpg