Please remember to post the list and not to us personally. Thanks! Actually, I don't know of a good way to do what you want to do (I thought I had an idea, but it won't work). One way to do this would be to select a random set of vertices. This would be approximately uniform. Alternatively, you can use mris_make_face_parcellation but you will be limited by the icosahedral series. If you want to go with the first option, you can run

mri_volsynth --temp subject/surf/lh.thickness --pdf uniform --o junk.mgh

mri_binarize --i junk.mgh --min .9 --o mask.mgh

The first command synthesizes a surface overlay with uniformly distributed random numbers between 0 and 1. The second command thresholds at .9, so you'd get about 10% of the vertices

doug

On 02/13/2014 02:20 AM, peng wrote:

Hi Douglas,

   Thanks for your reply. Yes, I mean "a mask surface overlay with 1s in some vertices and 0s in others". And I also wish to convert there coordinates back to the volume coordinates later (e.g. RAS etc.), which I think is possible.

On Wed, Feb 12, 2014 at 4:15 PM, Douglas Greve <greve@nmr.mgh.harvard.edu <mailto:greve@nmr.mgh.harvard.edu>> wrote:


    what do you mean by "dots"? Eg, a mask surface overlay with 1s in
    some vertices and 0s in others? Or a label?
    doug




    On 2/12/14 9:52 AM, peng wrote:

    Dear Freesurfers,

       I have run recon-all and got a set of surfaces for the
    subjects. I wish to distribute N dots about evenly on the surface
    to cover most gyri and sulci , but I don't how to implement that.
    One way is to manually put them in the GUI of freeview, but it is
    not so convenient if N is relative large (say, 200). Can anyone
    give me a hint which function shall I use?


    best
    Peng


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