Complex sentence: Close Range Photogrammetry (CRP) is a sub-set of photogrammetry and is differentiated from Aerial Photogrammetry in that the input photographs are taken from the ground or at closer range to the subject Atkinson 1996: p.9 Luhman 2006: p.2.
Split into simpler sentences: Close Range Photogrammetry (CRP) is a sub-set of photogrammetry and is differentiated from Aerial Photogrammetry by the type of input photographs. In CRP photographs are taken from the ground or at closer range to the subject Atkinson 1996: p.9 Luhman 2006: p.2.