1. Along a survey line. An inline geophone array has all the geophones located along the seismic line. An inline electromagnetic configuration has the source and receiver on the traverse line. (Not to be confused with ‘‘on-line’’ versus ‘‘off-line’’ in computer applications.) 2. For 3D data, the inline direction is (a) that in which the survey was acquired, where 3D data were acquired as a series of parallel lines, or (b) the direction of the line of sources, where acquired by perpendicular source and receiver lines, or (c) an arbitrary direction where acquired in other ways.