ECDIS - is a shipborne navigational system whose performance standards are specified in IMO Resolution A.817(19). It must support the whole range of navigational functions that make use of the characteristics of the chart data and their specific presentation. Moreover, to be an ECDIS, the equipment must be shown to meet all the requirement of the IMO Performance Standards and offer, besides the graphic presentation of chart data, additional information about the characteristics of the displayed features.
Within the ECDIS, the ENC database stores the chart information in the form of geographic objects represented by point, line and area shapes, carrying individual attributes which make any of these objects unique. Appropriate mechanisms are built into the system to query the data and then to use the obtained information to perform certain navigational functions (e.g. anti-grounding surveillance). The presentation of the current position, range/bearing functions and route planning capabilities are other examples of the minimum ECDIS requirements laid down in IMO Performance Standards.
Extracted from : Bridge Procedures Guide, 4th Ed.