ECDIS & Electronic Charts Explained: admiralty AVCS vs ARCS vs AIO vs ADC
admiralty quick guide to enc (electronic charts) for ECDIS: what AVCS, ARCS, AIO and ADC are, how they differ, and how official ENC updates, S-57/S-63 protection, and the S-100 transition affect your bridge routine.
Admiralty Eletronic Nautical Charts:
- ECDIS satisfies SOLAS chart-carriage rules when used with official ENCs, kept up to date, and with approved backups.
- AVCS = official vector ENC service. ARCS = official raster charts. AIO = overlay with T&P notices to de-risk passage planning. ADC = digital catalogue to find/manage coverage.
- Today’s ENCs are S-57 protected by S-63. The future is S-100 (e.g., S-101 ENCs) with richer, interoperable layers.
What is ECDIS?
The Electronic Chart Display and Information System (ECDIS) is a type-approved bridge system that can replace paper charts for SOLAS carriage when used with official ENCs, kept up to date, and supported by an approved backup arrangement. AVCS is essential for modern maritime navigation, providing detailed and updated vector information for safe passage. ECDIS can interrogate chart objects, trigger safety contours/alarms, and display overlays such as AIO for safer passage planning.
ENCs vs RNCs in plain language
ENCs (vector) are structured, object-based data (buoys, depths, TSS) that enable intelligent checks, alarms and scale-aware display. RNCs (raster) are georeferenced images of paper charts—faithful to the look and feel, but without object intelligence.
AVCS vs ARCS vs AIO vs ADC: Quick comparison
AVCS (Admiralty Vector Chart Service)
AVCS is the worldwide portfolio of official ENCs for ECDIS. It provides global coverage, weekly updates, and compatibility with the AIO overlay. For most routes and audits, AVCS is the default choice for compliant, intelligent vector charts.
ARCS (Admiralty Raster Chart Service)
ARCS delivers official raster versions of Admiralty paper charts. It is particularly useful in rare areas where ENC coverage is not yet available. Whether ARCS can be used as a primary means depends on Flag/Port State acceptance—ENCs remain the norm on ECDIS.
AIO (Admiralty Information Overlay)
The Admiralty Information Overlay adds Temporary & Preliminary (T&P) Notices to Mariners and related planning information as a transparent layer over your ENCs. Updated weekly alongside AVCS, AIO helps bridge teams spot potential risks early in the planning phase.
ADC (Admiralty Digital Catalogue)
The Admiralty Digital Catalogue helps you discover and manage coverage—by route, area, or scale band—across AVCS, ARCS, paper charts and publications. It’s the fastest way to ensure you have exactly the cells you need before you sail.
Compliance corner: SOLAS, updates & backups
- SOLAS carriage: Type-approved ECDIS + official ENCs + timely updates + approved backup arrangement.
- Evidence: Keep permit files, update logs/reports and AIO evidence together for inspections.
- Process: Standardise a simple SOP—permits → weekly media → verify → evidence.
S-57/S-63 today → S-100/S-101 tomorrow
Most ENCs in service today are produced in S-57 and protected by S-63 licensing and encryption. The next generation is the S-100 framework. Its flagship is S-101 ENCs, designed to interoperate with richer layers such as S-102 bathymetry and S-124 navigational warnings—enabling better data fusion on modern ECDIS.
How weekly updates are delivered
Official services publish weekly updates that you load into ECDIS or planning software. AIO is updated on the same rhythm. Your SOP should include permit checks, applying updates, verifying status, and saving proof (exported report or timestamped screenshot).
Quick checklist: From permit to proof
- Import/Renew permits for all voyage cells; re-request any failures.
- Apply base + weekly updates from the latest media; re-run if files were skipped.
- Verify status – open cell report in ECDIS; confirm all cells are Current; check AIO date.
- Save evidence – export report or take a timestamped screenshot to your “Chart Updates” folder.
- Re-check route – scan AIO/T&P along track for new restrictions, depths, or buoyage changes.
Tip: Keep a standard “Chart Updates” folder per voyage to make inspections painless.
Make your updates effortless
We can automate all the weekly updates, integrity checks and evidence capture—while keeping ECDIS offline.
FAQs
Is ECDIS alone enough to satisfy SOLAS?
Yes—when it’s type-approved and used with official ENCs kept up to date, plus an approved backup arrangement.
What’s the difference between AVCS and ARCS?
AVCS provides official vector ENCs that power alarms and object queries. ARCS provides official raster charts—useful in coverage gaps; primary use depends on Flag/Port acceptance.
What exactly is AIO?
An overlay with Temporary & Preliminary Notices and related planning info that displays on top of ENCs—updated weekly with AVCS.
What is ADC used for?
The Admiralty Digital Catalogue helps you search and manage coverage by route/region/scale, so you order exactly the cells you need.
What changes with S-100/S-101?
S-100 enables interoperable layers; S-101 ENCs are the successor to S-57 with richer structures and better integration with products like S-102 and S-124.