Checks if the input is a valid file path or numeric vector. If a .mgh file
path is provided, it automatically loads it. Validates that the number of
vertices matches the specified FreeSurfer template.
Usage
check_hemi(hemi, fs_template)
Arguments
- hemi
A numeric vector, a character string representing a file path
(e.g., .mgh, .gii), or NULL.
- fs_template
A character string specifying the FreeSurfer template
(e.g., "fsaverage5", "fsaverage").
Value
A numeric vector representing the surface data, or NULL if the input is NULL.
