IMO (International Maritime Organization) requires most of the Ocean-going vessels to carry ECDIS (Electronic Chart Display and Information System) by the SOLAS Convention and all the officers to be trained by the 2010 Manila Amendments to the STCW Convention and Code. Nowadays most of the vessels, including not only ocean-going but also domestic vessels, are equipped with ECDIS. It has a wide range of characteristics, such as indication of the ship's position, the heading and the speed through the water, navigation and/or monitoring alert systems in addition to information obtained from traditional paper nautical charts. However, too much information may cause burdens on its users because the size of ECDIS display screen is smaller than that of traditional paper charts. Equipment with a higher degree of usability would provide information more efficiently.
The authors conduct investigation for the usable display system of chart information under geographically and/or environmentally restricted situations. This investigation is aimed at license holders in order to consider a concept of combination appropriate for these situations. In this paper, the authors describe the results of the investigation and propose the concept.
