Electronic Navigational Chart (ENC)

An ENC is a vector chart database issued by an authorized hydrographic office and built to the IHO S-57 product specification, edition 3.1. It carries depth contours, soundings, navigation marks, and other features as discrete objects with attributes, which lets ECDIS apply safety contours, generate alarms, and interrogate any feature. ENC data is referenced to WGS-84 and loaded into the system as a SENC. The successor framework is the S-100 universal hydrographic data model, with S-101 as the next-generation ENC specification.