Using Workbench Command

CONVERT A WARPFIELD BETWEEN CONVENTIONS
   wb_command -convert-warpfield

      [-from-world] - input is a NIFTI 'world' warpfield
         <input> - the input warpfield

      [-from-itk] - input is an ITK warpfield
         <input> - the input warpfield

      [-from-fnirt] - input is a fnirt warpfield
         <input> - the input warpfield
         <source-volume> - the source volume used when generating the input
            warpfield

         [-absolute] - warpfield was written in absolute convention, rather
            than relative

      [-to-world] - write output as a NIFTI 'world' warpfield
         <output> - output - the output warpfield

      [-to-itk] - write output as an ITK warpfield
         <output> - output - the output warpfield

      [-to-fnirt] - repeatable - write output as a fnirt warpfield
         <output> - output - the output warpfield
         <source-volume> - the volume you want to apply the warpfield to

      NIFTI world warpfields can be used directly on mm coordinates via
      sampling the three subvolumes at the coordinate and adding the sampled
      values to the coordinate vector.  They use the NIFTI coordinate system,
      that is, X is left to right, Y is posterior to anterior, and Z is
      inferior to superior.

      NOTE: this command does not invert the warpfield, and to warp a surface,
      you must use the inverse of the warpfield that warps the corresponding
      volume.

      The ITK format is used by ANTS.

      You must specify exactly one -from option, but you may specify multiple
      -to options, and -to-fnirt may be specified more than once.