The increase in engineering work on the continental shelf over the past decade has been matched by the development and wider use of electronic positioning systems designed specially for survey work rather than navigation. This is just as well in view of the oil industry’s requirement for reliable survey plans at scales of 1/5 000 or 1/10 000 at distances of 300 kilometres or more from shore, and in depths of water which may exceed 200 metres. Part I discusses the determination of position in this context; Part II gives a brief description of the requirements of a drilling rig site survey
