Huibert-Jan Lekkerkerk is a contributing editor for GIM International and Hydro International and author of other various publications on GNSS and hydrography. He is a part-time senior lecturer in hydrography at the Maritime Institute Willem Barentsz (Cat A) and Skilltrade (Cat B) in the Netherlands. He also works as a consultant specialized in the specification and control of projects from an information management and hydrographic perspective.