Electronic Chart Display and Information SystemBased on vectorial representation of features, this system is the best available as it can be coupled to many other devices. Unfortunately since the availability of GPS positioning many hydrographic information have be found to be out of position by several miles at times (ie : Providence channel in the Bahamas),therefore many charts must be redrawn. It is only with these charts that electronic facilities, such as automatic alarms for shallow water, can be connected.