Electronic Chart Display and Information System

ECDIS is the modern successor to the paper chart on the bridge of most merchant ships. It is a type-approved computer system that displays Electronic Navigational Charts (official vector charts issued by national hydrographic offices) and continuously plots the ship's position on them using inputs from GPS, the gyrocompass, the speed log and other sensors. Because SOLAS now mandates ECDIS for most large ships, it has become the primary means of navigation, and used correctly it makes route planning and monitoring faster, clearer and safer than working solely on paper.

ECDIS does far more than draw a chart. The navigator plans a route on it and the system continuously monitors the ship against that plan, giving alarms and warnings if the vessel is standing into danger — approaching shallow water, a charted hazard, or a boundary the navigator has set. It integrates other information, overlaying radar and AIS targets, showing tidal and current data, and automatically applying chart corrections from official updates, which removes the laborious manual correction that paper charts required. Safety settings such as the safety contour and safety depth let the navigator tell the system what water is dangerous for that particular ship.

With this power comes the need for discipline and training. ECDIS is only as safe as its set-up and the competence of the user: wrongly configured safety settings, over-reliance on the display without keeping a proper lookout, or failing to understand the system's alarms have all contributed to groundings. For this reason STCW requires both generic and type-specific ECDIS training, and ships carry a backup arrangement (a second ECDIS or an appropriate paper chart folio) so that a single failure does not leave the bridge without a means of navigation. Properly used, ECDIS is among the most significant safety advances in modern navigation.