and from model space to data space as
where z is depth in the data space, is the aperture angle, z' is the depth in the model space, q is the moveout curvature and h is the lateral apex shift. In this way, we transform the two-dimensional data space of ADCIGs, , into a three-dimensional model space, m(z',q,h).
In the ideal case, primaries would be perfectly horizontal in the ADCIGs and would thus map in the model space to the zero-curvature (q=0) plane, i.e., a plane of dimensions depth and apex-shift distance (h,z'). Specularly-reflected multiples would map to the zero apex-shift distance (h=0) plane, i.e., a plane of dimensions depth and curvature (q,z'). Diffracted multiples would map elsewhere in the cube depending on their curvature and apex-shift distance.