The need for time varying objects in the electronic charts (ECDIS)

The idea of an Electronic Navigational Chart (ENC) is being developed into a commercially viable Electronic Chart Display and Information System (ECDIS). However, the full potential of the system is not likely to be realised until time varying objects (TVO) like tides, currents, tidal streams, magnetic variation, ice, etc., are incorporated to represent the constantly changing conditions that meet the navigators every day. To do it effectively, we need a “paradigm shift”. So far, we have been presenting the dynamic time variables in a static form to suit the constraints of the paper chart. This traditional, static approach is not relevant to ECDIS, and we need to move towards a dynamic presentation of tides and other time variables. It is proposed that the whole relationship of TVO information to the chart be re-assessed in view of the dynamic abilities of ECDIS. We have to consider the TVO and charts as two sides of the same dynamic entity, and not as separate issues. The ENC Database supporting ECDIS operations is being developed as a complete world-wide system. The TVO information, in some form, will be a part of this database, and we should look at this data as a part of digital chart service rather than a stand-alone service like tide tables. The ECDIS of the future is expected to be a four-dimensional dynamic system providing a seamless presentation of temporally varying depths, streams, currents, and other TVO. Developments in TVO applications in ECDIS aiming for such a system will depend on two main factors: availability of digital data and computing power available to ECDIS. In addition, several questions need to be answered before addressing the technical problems connected with introducing the time variables into ECDIS. To answer them, we need to look towards future possibilities as much as at the solutions viable at present