@ElectroGrid <[-strip Nx] | [-grid Nx Ny]>
              [-prefix PREFIX] [-coords XYZ.1D]

Creates a mesh representation of an electrode grid for use with SUMA

Mandatory parameters:
   One of the two options -strip or -grid

   -strip Nx: Make an Nx strip (array) of electrodes.

   -grid Nx Ny: Make an Nx by Ny grid of electrodes.
                A node at (i,j) has a node ID = i+Nx*j with
                0<=i<Nx and 0<=j<=Ny

Optional parameters:
   -coords XYZ.1D: Specify the coordinates of the nodes on the grid,
                   or the array. XYZ.1D should have three columns,
                   with each row specifying the coordinates of one node.
                   You can use sub-brick selectors to select from more
                   than three columns.

                   The fist row is for node 0, second for node 1, etc.
                   The ordering is trivial for an array. For a grid you
                   need to be a bit more careful. You march along the x
                   direction first, then move up the y.
                   A flat grid (Z=0) for a 2x3 electrodes system would
                   have coordinates layed out as such:
                #  X Y Z   (ID shown here for clarity)
                   0 0 0            0
                   1 0 0            1
                   0 1 0            2
                   1 1 0            3
                   0 2 0            4
                   1 2 0            5

                   Usually, you would have coordinates in the subject's
                   anatomical space.

   [-prefix PREFIX]: Use PREFIX for the output surface.
   [-with_markers]: Add markers to the surface at each electrode. See
                    examples below for detail.
   [-echo]    : set echo

   Make a flat 4 electrode array:
   Node X coordinates are regularly spaced from 0 to 3.
   Node Y coordinates are small and random, to allow array
   representation as a surface

      @ElectroGrid -prefix flat4 -strip 4
      suma -i flat4.gii

   Make a flat 4 electrode array and assign anatomical coordinates
   in first three columns of file:   HPelectrodes_AF.1D

      @ElectroGrid -prefix HP_array -strip 4 \
                   -coords  HPelectrodes_AF.1D'[0,1,2]'
      suma -i HP_array.gii

   Make a 2x3 flat grid:
   Node coordinates are on a regular grid.

      @ElectroGrid -prefix flat23 \
                   -grid 2 3
      suma -i flat23.gii

   Make an 8x8 grid, and assign to its nodes the coordinates listed
   in the first three columns of HPelectrodes_Grid.1D

      @ElectroGrid -prefix HP_grid \
                   -coords HPelectrodes_Grid.1D'[0,1,2]' \
                   -grid 8 8
      suma -i HP_grid.gii

   Say you're too lazy to know the grid (or strip) count
   and you have a file with the electrode's coordinates.

      @ElectroGrid -prefix HP_grid2 \
                   -coords HPelectrodes_Grid.1D'[0,1,2]'
      suma -i HP_grid2.gii

   You can also give the grid a special appearance by adding
   special node markers. For example, put the following text
   in file marker.niml.do
   echo "\
     <nido_head coord_type = 'mobile' /> \
     <S rad = '2' style = 'silhouette' stacks = '20' slices = '20' /> \
   " > marker.niml.do
   Then create a spec file for one of the grid surfaces:
     quickspec -spec grid.spec \
               -tsnadm gii pial HP_grid2.gii y SAME marker.niml.do
     suma -spec grid.spec

   Using option -with_markers will do the trick for you.

Ziad Saad (saadz@mail.nih.gov)
SSCC/NIMH/ National Institutes of Health, Bethesda Maryland