WHOI-90-52

Introduction
The Status and Promi of Electronic Chart
Mortmer Rogoff
Radio Technica Commission for Martime Services (RTCM)
The martime world is about to enter a new decde with the expetation that it wil
benefit from
new technology applied to ship handling and safe navigation. These changes wil result from the
introduction and widespread use of a varety of systems of electronic chars.
Electronic chars are the equivalent of conventional paper nautica chars that are create by a
computer on board a vessel and displayed to the user by meas of an electronic screen. They
are almost always coupled to an electronic navigation system, resulting in the display of the
vessel's position on the electronic char and as an option ca also be connecte to the vessel's
rad. Doing so adds an image of the situation surrounding the vessel, showing other vessels
and the position of aids to navigation and objects on shore.
An electronic char system is endowed with varing degrees of capabilty and sophistication,
depending upon the use for which it is designed, the stadads it is intended to meet and the
price at which it is offered. These rage from the units intended for use aboard yachts and
pleasure craft to those designed to be instaled on large, deep draft oc-going vessels that move
around the world. The units on recreational vessels generaly possess just one smaller display
screen of medium to low resolution and are intended to be an additional aid to the navigation of
the vessel. At the other extreme, larger systems place on commercial vessels may possess two
or even three displays, use large screens of high resolution, employ a radar overlay and are
intended to be the legal equivalent of a paper nautica char.
An importt aspet of electronic chars -- a quality that sets them apar from virtally all other
forms of martime electronics -- is the fact that the nautica char is a legal document. Paper
chars are accted in courts of law as the meas for describing vessel movements before and at
the time of accidents and in some cases may actually be the cause of legal action if the chars
are found to be in error. The legal nature of the electronic char implies that if it is to be widely
accepted by users, it must be acceptable to legal authorities. Fortunately, this is increasingly the
case and provisional stadads prepared by international and national bodies are being issued.
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