The Grid Reference System

Traditionally, in archaeology the site is divided into squares with the aid of ropes and cables. This system enables us to provide each object with a set of coordinates determining its position.

In underwater archaeology, usually a mobile grid system, firmly anchored to the ocean bed, is used. The grid can be sledded along the fixed reference lines, the baselines. The base mesh of a grid usually measures 1m x 1m. The preferred method is, however, the electronic one. Nowadays, underwater positioning systems DGPS can achieve a degree of precision within centimetres. The grid will be limited in the future to help the diver determine his own position, particularly in poor visibility, which can at worst be within centimetres.