Extended Operational and Trade Vocabulary

Marine Hydrography, Charting and ENC glossary

The hydrographic-charting vocabulary: the ENC usage bands (A1 Overview through A5 Harbour) in the S-57 navigational-purpose hierarchy, the migration to S-100, survey orders under S-44, and the chart-production and ENC-encoding terms. Grounds each term in the IHO standard or the charting process it belongs to.

439 defined terms.

Showing 250 on this page (page 1 of 2).

A

A1 Cell: An ENC cell at usage band 1 (Overview), the smallest scale in the S-57 navigational purpose hierarchy.
A2 Cell: An ENC cell at usage band 2 (General), used for ocean and offshore passage planning.
A3 Cell: An ENC cell at usage band 3 (Coastal), used for coastwise navigation.
A4 Cell: An ENC cell at usage band 4 (Approach), used when approaching ports and channels.
A5 Cell: An ENC cell at usage band 5 (Harbour), used inside port limits and confined waters.
A6 Cell: An ENC cell at usage band 6 (Berthing), the largest scale used for berth-by-berth operations.
Above Water Rock: An ENC object (OBSTRN/UWTROC subtype) representing rock features permanently above chart datum.
Accuracy of Position: The ENC attribute POSACC, recorded in metres of horizontal uncertainty for charted features.
Active Captain: A community crowd-sourced points-of-interest layer integrated by Garmin into recreational ENC displays.
Admiralty: The UKHO trademarked brand under which UK official nautical charts and publications have been issued since 1795.
Admiralty Chart: Nautical chart issued by the UK Hydrographic Office.
Admiralty Chart 5011: The official UKHO booklet of symbols and abbreviations used on Admiralty paper charts.
Admiralty Digital Catalogue: The electronic index of all Admiralty paper charts, ENCs, and publications, updated weekly.
Admiralty Digital List of Lights: ADLL, the UKHO digital equivalent of the paper List of Lights and Fog Signals.
Admiralty Digital Publications: ADP, the UKHO suite of electronic nautical publications including ADLL, ADRS, and e-NP.
Admiralty e-Navigator: The UKHO desktop planning and chart management application for managing ENC and publication holdings.
Admiralty e-NP: Electronic Nautical Publications, the UKHO PDF and software replacements for printed Sailing Directions, ALRS, and ALL.
Admiralty EasyTide: The free UKHO online tidal prediction service for ports worldwide.
Admiralty Information Overlay: AIO, an ENC overlay distributed by UKHO containing T&P NMs and ENC preliminary information.
Admiralty List of Lights and Fog Signals: ALL, the eleven-volume UKHO publication listing maritime lights worldwide.
Admiralty List of Radio Signals: ALRS, a UKHO publication in six volumes covering GMDSS, port operations, satellite, and meteorological radio services.
Admiralty Notices to Mariners: The weekly UKHO bulletin promulgating chart corrections to Admiralty charts and publications.
Admiralty Raster Chart Service: ARCS, the UKHO raster equivalent of paper charts, encrypted for use in Type Approved systems.
Admiralty Tide Tables: ATT, the four-volume UKHO publication of daily tidal predictions for standard and secondary ports.
Admiralty TotalTide: ATT software providing seven-day tidal height and stream predictions for over 7,000 ports.
Admiralty Vector Chart Service: AVCS, the official UKHO worldwide ENC distribution service covering virtually all commercial routes.
Aft Perpendicular: Reference station at the after side of the rudder post or rudder stock centerline used in naval architecture drawings.
AHO: Australian Hydrographic Office, headquartered in Wollongong, New South Wales, and producer of Australian official charts.
Aids to navigation: AtoN, IALA classified marine aids.
Airborne Bathymetric LIDAR: A laser-based remote sensing method for shallow-water depth measurement, used by IHO members in clear coastal waters.
Alaska Coastal Survey: A NOAA Office of Coast Survey programme covering Alaskan waters, where many areas remain Zone of Confidence U.
ALL: Admiralty List of Lights and Fog Signals.
ALRS: Admiralty List of Radio Signals (Vols 1-6).
Anchorage Area: ENC object ACHARE representing a designated area where vessels may anchor.
ANP: Area to be Avoided, a charted routeing measure adopted under IMO Resolution A.572.
ARCS: Admiralty Raster Chart Service.
Area Notice: An AIS Application-Specific Message conveying temporary navigational information, sometimes used in lieu of T&P NMs.
Argentine Hydrographic Service: Servicio de Hidrografia Naval (SHN), based in Buenos Aires.
ATT: Admiralty Tide Tables.
ATX Format: A historical Admiralty exchange container format for ENC distribution, superseded by S-63 exchange sets.
AUSREP: Australian Ship Reporting System, coordinated with chart products of the AHO and Joint Rescue Coordination Centre Australia.
Australian Hydrographic Office: AHO, the Royal Australian Navy unit at Wollongong producing AUS-prefix paper charts and AU-cell ENCs.
Australian Hydrographic Service: The former name of the AHO before 2017 corporate restructuring.
AVCS: Admiralty Vector Chart Service.

B

Backscatter: Acoustic or radar energy returning toward the source.
Bands of Usage: The six S-57 navigational purpose categories from Overview (1) to Berthing (6).
Base Cell: The .000 file in an S-57 exchange set, containing the full ENC dataset before any update files are applied.
Bathymetric ENC: A non-navigational ENC variant carrying high-resolution depth data, formalised under S-102.
Bathymetric Surface: The IHO S-102 product specification for gridded bathymetric data within the S-100 framework.
Bathymetry: Measurement and mapping of seafloor depth.
BCnav: A discontinued Canadian Hydrographic Service raster chart product, replaced by official ENCs.
Beacon: Fixed AtoN, lit or unlit.
Beam Spacing: The angular distance between adjacent multibeam echo sounder beams, governing across-track resolution.
Berthing: Usage band 6 in the ENC scale hierarchy, intended for berth-side operations.
BIRD: Bottom Image and Reflectivity Data, a generic term for sidescan and multibeam backscatter products.
Black Sea Hydrographic Commission: BSHC, the IHO regional hydrographic commission for Black Sea states.
BlueOS: Open-source ROV operating system used in small-platform hydrographic surveys.
Boundary Cell: An ENC cell containing the metadata polygon at the limit of a producer's area of responsibility.
Brazilian Directorate of Hydrography and Navigation: Diretoria de Hidrografia e Navegacao (DHN), in Niteroi.
Brest: French Atlantic naval port and arsenal developed under Richelieu and Colbert in the seventeenth century.
BSH: German Federal Maritime and Hydrographic Agency responsible for offshore wind permitting in the German EEZ.
Bundesamt fur Seeschifffahrt und Hydrographie: The full German name of BSH, producer of German official charts and ENCs.
Buoy: Floating navigation mark or float used to mark a mooring.
Busan: The headquarters city of the Korea Hydrographic and Oceanographic Agency.

C

C-MAP: A vector chart brand originally of Norway, now part of Navico Group, producing CM93 and ECDIS-grade ENCs.
C-MAP MAX: The recreational vector chart product line from C-MAP for chart plotters.
C-MAP Professional+: The ECDIS-grade ENC service from C-MAP licensed under S-63.
Cable: Unit of length of one-tenth of a nautical mile, 185.2 m.
Cadiz: The seat of the Spanish Instituto Hidrografico de la Marina (IHM).
Canadian Hydrographic Service: CHS, the federal HO with offices in Ottawa, Sidney BC, Mont-Joli, and Burlington.
Cartographic Generalisation: The reduction and simplification of charted features when compiling smaller-scale ENCs from source data.
Cat Zoc: Category of Zone of Confidence, the S-57 attribute CATZOC encoded A1, A2, B, C, D, or U for survey reliability.
CCRP: Common Coordinate Reference Point, the survey reference origin to which all sensor offsets are reduced.
Cell: Discrete electrochemical area on a steel surface where corrosion or protection currents flow.
Cell Permit: An S-63 encrypted authorisation that unlocks one ENC cell for a defined period.
Central Commission for Navigation of the Rhine: CCNR, the inland regulator whose Inland ENC specification predates the S-100 framework.
Centralised Route Scheduling: CRS+, a ChartCo ENC update management service.
CHART 1: The NOAA equivalent of UKHO Chart 5011, the United States chart symbols booklet.
Chart Correction Log: A vessel-side record of NMs applied to each chart and ENC cell, required by SOLAS V.
Chart datum: Lowest astronomical tide reference for hydrographic charts.
Chart Plotter: A non-Type Approved electronic chart display intended for recreational use, distinct from ECDIS.
ChartCo: A UK-based ENC distributor and update service provider, now part of OneOcean Group.
ChartWorld: A German-headquartered ENC distributor and ECDIS service provider.
CHRIS: Committee on Hydrographic Requirements for Information Systems, the former IHO body whose work passed to HSSC.
CHS: Continuous Hull Survey, cyclical scheme spreading special survey items over five years.
CIRM: Comite International Radio-Maritime, marine electronics industry body.
Co-NAVIGATIO: An ENC distribution initiative coordinated through Primar.
Coastal: Usage band 3 in the ENC scale hierarchy, intended for coastwise navigation.
Coastline: ENC object COALNE representing the line of mean high water or equivalent.
Compilation Scale: The intended display scale of an ENC cell, encoded in the M_CSCL meta object.
Continental Shelf: Seabed and subsoil beyond territorial sea, up to the outer edge of the continental margin or 200 nm.
Contour Interval: The vertical spacing between depth contours selected by a producer for an ENC cell.
Coverage Cell: An ENC cell that defines the M_COVR area of coverage for a producer's product.
CRS: Croatian Register of Shipping, IACS member headquartered in Split.

D

Danish Geodata Agency: GST (Geodatastyrelsen), the Danish HO in Copenhagen.
Danish Hydrographic Office: Historical term for the Royal Danish Administration of Navigation and Hydrography, now within Geodatastyrelsen.
Dataset: A single S-57 ENC file or update; one of the .000, .001, .002 sequence.
Datum: The horizontal or vertical reference frame; ENC horizontal datum is mandatorily WGS-84.
Decca Chart: A historic lattice chart for Decca Navigator hyperbolic fixing, withdrawn from carriage requirements after 2000.
Deep Contour: The depth contour selected by the ECDIS operator beyond which the vessel may safely navigate without grounding risk.
Deep-sea lead: Hand sounding lead, historical practice.
Dehradun: The headquarters city of the Indian National Hydrographic Office.
Depth Area: ENC object DEPARE describing a region bounded by two depth values.
Depth Contour: ENC object DEPCNT representing a line of constant depth.
Depth of Navigation: A safety contour value compared against the four-shade depth display in ECDIS.
DGPS: Differential GPS using IALA radio beacons.
DHN: Diretoria de Hidrografia e Navegacao, the Brazilian Navy hydrographic directorate.
DHN Niteroi: The headquarters of the Brazilian DHN.
Differential Update: The S-57 .001, .002, ... incremental files applied to a base cell to reflect chart corrections.
Display Category: The S-52 grouping of ENC features into Base, Standard, and Other display layers.
dKart: An ENC production toolset family supporting S-57 producers worldwide.
DKART Editor: A Russian-developed ENC production and editing software suite by Morintech.
DNC: Digital Nautical Chart, the US National Geospatial-Intelligence Agency military vector chart product, distinct from US ENC.
DoT NOAA: The United States Department of Commerce parent agency of NOAA Office of Coast Survey.
DSM: Data Server Module, a category of S-100 service component.
Dual Fuel ENC: Informal term for vessels carrying both ENC and paper backup, permitted under SOLAS V/19.2.1.5.
Duplicate Cell: An ENC cell issued by more than one producer; resolved under IHO WEND principles in favour of the coastal state.

E

e-Navigation: The IMO strategy for harmonised electronic navigation systems, underpinned by S-100 product specifications.
e-Navigator: See Admiralty e-Navigator.
EAtHC: East Asia Hydrographic Commission, the IHO regional commission for East Asian member states.
ECDIS: Electronic Chart Display and Information System per IMO MSC.232(82).
ECDIS Chart 1: A test dataset distributed in S-64 demonstrating the full range of S-52 portrayal.
ECDIS Kernel: The licensed software library performing S-52 portrayal and S-57 reading, typically supplied by SevenCs, Adveto, or Transas.
eChart: Generic term for any electronic nautical chart, encompassing both ENC and RNC formats.
EdgeTech 3300: Hull or pole-mounted chirp sub-bottom profiler from EdgeTech for shallow stratigraphy imaging.
EM 122: Kongsberg deep water multibeam echo sounder operating at 12 kHz for full ocean depth bathymetric mapping.
EM 124: Kongsberg deep water multibeam echo sounder that succeeds the EM 122 with improved swath performance.
EM 2040: Kongsberg high-resolution shallow water multibeam echo sounder for inshore and coastal bathymetry.
EM 304: Kongsberg full ocean depth multibeam echo sounder positioned between the EM 124 and the deeper EM 2040 family.
EM 712: Kongsberg medium water multibeam echo sounder used on survey vessels for shelf and slope mapping.
ENC: Electronic Navigational Chart, an S-57 (and future S-101) compliant vector dataset issued by or under the authority of a national HO.
ENC Cell: See Cell.
ENC Maintenance: The continuous update cycle of issuing new editions, re-issues, and updates for ENC cells.
ENC Producer Code: The two-character country code and four-character agency code combination from IHO S-62.
ENC Update: A .001 or higher incremental file applied to a base cell.
ENP: Electronic Nautical Publication.
Equator: Great circle equidistant from the geographic poles.
ERNP: European Radio Navigation Plan, providing context for European HO chart datum and AtoN policy.
eSF: Electronic Stowage Factor, unrelated to charting but commonly confused with ENC terms.
ESRI Maritime: ESRI's family of nautical chart production and ENC editing tools built on the ArcGIS platform.
Estuary: Semi-enclosed coastal body of water where freshwater meets seawater.
EUDP: European Union Datum Programme, supporting harmonisation of European ENC horizontal references.

F

F-NAV: A historical informal abbreviation for fleet navigation services using chart correction subscriptions.
Fairway: Navigable channel.
Feature Object: An S-57 geographic object such as DEPARE, COALNE, or LIGHTS.
Federal Maritime and Hydrographic Agency: German BSH conducting examinations and approvals for navigation systems used by trainees.
FEMA: Used here for the IHO Frequently Updated Information dataset (FUI), not the US disaster agency.
Finnish Transport Infrastructure Agency: Vayla, the Finnish HO based in Helsinki.
Fishing Ground: ENC object FSHGRD representing an area where commercial fishing routinely occurs.
Floating Aid: A buoy or other AtoN not fixed to the seabed, charted with BOYxxx objects.
Fog signal: Audible signal under COLREGs Rule 35 in restricted visibility.
Folio: A printed Admiralty term for a bundled set of charts covering a region.
Forel-Ule Scale: A water colour scale of historical hydrographic interest, sometimes referenced in survey metadata.
Foul Area: An ENC object representing waters with numerous obstructions of uncertain position.
Foul Ground: ENC object OBSTRN with CATOBS value indicating foul ground.
Furuno NavSailor: Furuno's ECDIS product family, including the FMD-3200 and FMD-3300 series.

G

GEBCO: General Bathymetric Chart of the Oceans, providing global bathymetric grids.
GEBCO Grid: The latest version of the global gridded bathymetry product, currently issued as GEBCO_2024 and predecessors.
General: Usage band 2 in the ENC scale hierarchy.
Generalised Bathymetry: Reduced-resolution bathymetry used in small-scale ENCs.
Geodatastyrelsen: The Danish name of the Danish Geodata Agency (GST).
Geographic Cell Limit: The latitude and longitude bounds of an ENC cell.
Geoid: Equipotential surface of Earth's gravity field approximating mean sea level.
GeoSurv: Generic shorthand used for geophysical and bathymetric surveys feeding chart production.
GHA: Greenwich Hour Angle, an astro-navigation term retained in IHO publications for celestial corrections.
GIS: Geographic Information System, the broader software family from which ENC production systems derive.
GMDSS: Global Maritime Distress and Safety System under SOLAS Chapter IV.
GST: Geodatastyrelsen, the Danish Geodata Agency.
GUNiO: Glavnoye Upravleniye Navigatsii i Okeanografii, the Russian Federation Department of Navigation and Oceanography of the Ministry of Defence in Saint Petersburg.

H

Hamburg: German cruise homeport on the Elbe and base for Hapag-Lloyd Cruises.
Harbour: Usage band 5 in the ENC scale hierarchy.
Harbour Master Office: Charted on ENCs via the HRBFAC object class.
HDB: IHO Hydrographic Dictionary Database, the online derivative of S-32.
HEALPix: A spherical pixelisation scheme used in some bathymetric grid distributions.
HELCOM: Helsinki Commission protecting the Baltic Sea marine environment.
Helsinki: Finnish cruise port on the Baltic Sea.
High Density Cell: An informal term for ENCs with rich object content typical of harbour and berthing scales.
High Water: Highest tidal level reached.
HO: Hydrographic Office, the generic abbreviation for a national charting authority.
Horizontal Datum: WGS-84 is mandatory for ENC products under S-57 and S-101.
HSSC: Harmonized System of Survey and Certification under SOLAS, MARPOL, Load Lines, and BCH/IBC/IGC/BWM.
HYDRO Conference: The biennial UKHO international conference on hydrography.
Hydrographer of the Navy: The historical title held by the UKHO Chief Executive when UKHO was part of the Royal Navy.
Hydrographic Dictionary: IHO Publication S-32.
Hydrographic Office of the People's Liberation Army Navy: The Chinese national HO based in Tianjin.
Hydrographic survey: IHO S-44 compliant bathymetric survey.
Hydrography: Science of surveying water bodies.

I

IALA: International Association of Marine Aids to Navigation and Lighthouse Authorities.
IALA Buoyage System A: Used in most of the world, port hand red.
IALA Buoyage System B: Used in the Americas, Japan, Korea, Philippines, port hand green.
IBC Series: International Bathymetric Chart series, a regional initiative supporting GEBCO with finer-resolution products.
IBCAO: International Bathymetric Chart of the Arctic Ocean.
IBCM: International Bathymetric Chart of the Mediterranean.
IC-ENC: International Centre for Electronic Navigational Charts based in Taunton UK.
IENC: Inland ENC, the S-57 product specification for inland waterways under CCNR / UNECE.
IHB: International Hydrographic Bureau, the IHO Secretariat in Monaco; the former name of the IHO itself before 1970.
IHM: Inventory of Hazardous Materials required under HKC and EU SRR.
IHO: International Hydrographic Organization, intergovernmental body for hydrography.
IHO Council: The intergovernmental body advising on IHO programme priorities between Assemblies.
IHO Member State: A national government acceded to the IHO Convention; over 100 states as of 2024.
IHO Secretariat: The Monaco-based permanent staff supporting IHO work.
IIC Technologies: A Canadian-headquartered hydrographic services and ENC production company.
IIM: Istituto Idrografico della Marina, the Italian HO at Genoa, founded 1872.
IMO: International Maritime Organization, UN specialized agency for shipping safety, security, and pollution prevention.
Inco-NAV: Generic shorthand for inconsistent navigational information across multiple ENC producers.
Indian National Hydrographic Office: INHO, at Dehradun, producer of IN-prefix charts and ENCs.
INHO: Indian National Hydrographic Office.
Inland ECDIS: Standardized electronic chart system for European inland waterways.
Inland ENC: See IENC.
Inset: A larger-scale supplementary panel on a paper chart, conceptually replaced by higher usage band ENC cells.
Instituto Hidrografico de la Marina: The Spanish national HO at Cadiz.
Instituto Idrografico della Marina: The Italian national HO at Genoa.
International Centre for ENCs: IC-ENC, the RENC hosted at UKHO providing ENC validation and distribution.
International Chart: An INT chart, a paper chart series produced under IHO standardised specifications by member states.
International Hydrographic Organization: IHO, sets bathymetric and chart standards.
International Hydrographic Review: The IHO biannual technical journal.
IRCC: Inter-Regional Coordination Committee of the IHO.
Isolated Danger Mark: IALA mark with black body and one or more red bands and a topmark of two black spheres, placed over isolated hazards.
Issue Date: The date a new edition of an ENC cell becomes effective.

J

Japan Coast Guard: JCG, the agency under which JHOD operates.
Japan Hydrographic and Oceanographic Department: JHOD, part of the Japan Coast Guard in Tokyo.
Jeppesen Marine: Boeing subsidiary providing ENC distribution and route planning, now Jeppesen by Bing Maritime.
JHOD: Japan Hydrographic and Oceanographic Department.
Jib: Triangular headsail of a fore-and-aft rig.
JRC: Japan Radio Co., manufacturer of MF/HF, Inmarsat C and AIS equipment.
Junior Officer of the Watch: JOOW, a bridge role responsible for monitoring ECDIS settings during a watch.

K

Kartverket: The Norwegian Mapping Authority, parent of the Norwegian hydrographic service.
KHOA: Korea Hydrographic and Oceanographic Agency, in Busan.
Knot: One nautical mile per hour.
Knudsen Chirp: A widely deployed sub-bottom profiler product family used in hydrographic surveys.
Kongsberg EM Series: Kongsberg Maritime's family of multibeam echo sounders, including the EM 122, EM 124, EM 304, EM 712, and EM 2040.

L

Landmark: ENC object LNDMRK representing a conspicuous feature ashore used for visual navigation.
LAT: Lowest Astronomical Tide.
Latitude: Angular distance north or south of the equator.
Layer: tranche of cover in an excess of loss program.
Lead Line: Traditional weighted line for taking soundings.
Leading line: Line passing through two leading marks indicating a safe approach.
Levelling: Geodetic measurement of orthometric heights, used to relate land benchmarks to chart datum.
Lidar Bathymetry: Airborne or vessel-based laser scanning of shallow seabed.
Light: ENC object LIGHTS describing a navigational light's characteristics.
Light Float: Large, ship-shaped lighted buoy moored as a substitute for a light vessel.
Lighthouse: Tower with a navigational light.
LINZ: Land Information New Zealand, parent agency of the New Zealand Hydrographic Authority.
Local Notice to Mariners: NM issued by a port, regional authority, or coastguard for a defined area.
Logbook: Vessel record of fishing activity and catch.
Loran-C: Legacy hyperbolic radionavigation system.
Low Water: LW, the minimum tidal height in a tidal cycle, predicted in ATT and equivalent national tables.
Lubber line: Reference line on compass aligned with ship's head.

M

Magnetic variation: Angle between true and magnetic north at a location.
Map Projection: The mathematical transformation from the geoid to a flat surface; Mercator is dominant on paper charts.