Note that this reference documentation is identical to the help that is displayed in MATLAB when you type “help ft_prepare_layout”.
FT_PREPARE_LAYOUT loads or creates a 2-D layout of the channel locations. This layout is required for plotting the topographical distribution of the potential or field distribution, or for plotting timecourses in a topographical arrangement. Use as layout = ft_prepare_layout(cfg, data) There are several ways in which a 2-D layout can be made: it can be read directly from a *.mat file containing a variable 'lay', it can be created based on 3-D electrode or gradiometer positions in the configuration or in the data, or it can be created based on the specification of an electrode or gradiometer file. Layouts can also come from an ASCII *.lay file, but this type of layout is no longer recommended. You can specify any one of the following configuration options cfg.layout filename containg the layout (.mat or .lay file) can also be a layout structure, which is simply returned as-is (see below for details) cfg.rotate number, rotation around the z-axis in degrees (default = , which means automatic) cfg.projection string, 2D projection method can be 'stereographic', 'orthographic', 'polar', 'gnomic' or 'inverse' (default = 'polar') cfg.elec structure with electrode definition, or cfg.elecfile filename containing electrode definition cfg.grad structure with gradiometer definition, or cfg.gradfile filename containing gradiometer definition cfg.opto structure with optode structure definition, or cfg.optofile filename containing optode structure definition cfg.output filename (ending in .mat or .lay) to which the layout will be written (default = ) cfg.montage 'no' or a montage structure (default = 'no') cfg.image filename, use an image to construct a layout (e.g. useful for ECoG grids) cfg.bw if an image is used and bw = 1 transforms the image in black and white (default = 0, do not transform) cfg.overlap string, how to deal with overlapping channels when layout is constructed from a sensor configuration structure (can be 'shift' (shift the positions in 2D space to remove the overlap (default)), 'keep' (don't shift, retain the overlap), 'no' (throw error when overlap is present)) cfg.skipscale 'yes' or 'no', whether the scale should be included in the layout or not (default = 'no') cfg.skipcomnt 'yes' or 'no', whether the comment should be included in the layout or not (default = 'no') Alternatively the layout can be constructed from either data.elec structure with electrode positions data.grad structure with gradiometer definition data.opto structure with optode structure definition Alternatively you can specify the following layouts which will be generated for all channels present in the data. Note that these layouts are suitable for multiplotting, but not for topoplotting. cfg.layout = 'ordered' will give you a NxN ordered layout cfg.layout = 'vertical' will give you a Nx1 ordered layout cfg.layout = 'butterfly' will give you a layout with all channels on top of each other cfg.layout = 'circular' will distribute the channels on a circle The output layout structure will contain the following fields layout.label = Nx1 cell-array with channel labels layout.pos = Nx2 matrix with channel positions layout.width = Nx1 vector with the width of each box for multiplotting layout.height = Nx1 matrix with the height of each box for multiplotting layout.mask = optional cell-array with line segments that determine the area for topographic interpolation layout.outline = optional cell-array with line segments that represent the head, nose, ears, sulci or other anatomical features See also FT_TOPOPLOTER, FT_TOPOPLOTTFR, FT_MULTIPLOTER, FT_MULTIPLOTTFR, FT_PLOT_LAY