S-57 is a set of
regulations approved by IMO and IHO (the international organizations responsible
for the safety at sea requirements and related cartography) for standardization
of cartographic data exchange between Hydrographic Offices, Regional Chart
Distribution and ECDIS-producers.
S-57 chart comprises data of
two sort - spatial (location information about real world entities) and feature
(descriptive information about real world entities). Data in S-57 data set
(chart) is organized in objects. Spatial objects (e.g. node, edge, face)
possesses coordinates which define its location on the Earth's surface. Feature
object (e.g. BOYCAR - buoy cardinal, COALNE - coast line, LNDARE - land area)
contains attributes - qualitative or quantitative characteristics of the object.
Object may reference each other that enables simulation of arbitrary level of
complexity. Detailed information on S-57 may be found in IHO Transfer
Standard for Digital Hydrographic Data Edition 3.0 - March 1996. Special
Publication No 57.
To browse IHO
S-57 / ENC - Object and Attribute Catalogue online click here.
At the present moment there is a
transition from the old S-57 version 2 (also known as DX90) standard
specification to its last issue named S-57 version 3.