Information design in nautical charts

Conspicuous grey shading or blue colours are traditionally used in printed nautical charts to represent shallow water. The problem is that what is “deep” water for one size of ship might not be so for another size. To understand the extent of navigable water the bridge crew has to make a number of relatively complicated mental calculations. This paper suggests an automatic way of displaying NoGo areas that will give the bridge officer an at-a-glance knowledge of his ship’s manoeuvrable space, present and along the future route. A prototype has been developed and was tested with professional mariners in the EU project ACCSEAS. The system was rated as good and acceptable from a professional point of view although further improvements are necessary.