Nationwide Automatic Identification System 2025

Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and international waters in real-time. In the U.S. the Coast Guard and industry collect AIS data, which can also be used for a variety of coastal management purposes. NOAA and BOEM have worked jointly to make available these data from the U.S. Coast Guards national network of AIS receivers. The original records were filtered to a one-minute frequency rate, and subset to depict the location and description of vessels broadcasting within the Exclusive Economic Zone.

To support ocean planning activities pursuant to the Executive Order Regarding the Ocean Policy to Advance the Economic, Security, and Environmental Interests of the United States, the Energy Policy Act, the Rivers and Harbors Act, and the Coastal Zone Management Act.

Bureau Code: 006:48, Program Code: 006:055

MMIS, BaseDateTime, LAT, LON, SOG, COG, Heading, VesselName, IMO, CallSign, VesselType, Status, Length, Width, Draft, Cargo, TransceiverClass (see more here: https://coast.noaa.gov/data/marinecadastre/ais/data-dictionary.pdf)

https://www.marinecadastre.gov/about/disclaimer.html

None

For coastal and ocean planning

Compiled to meet 10 meters horizontal accuracy at 95% confidence level

Presence and absence of a record is dependent on the:

a) Fixed and unpublished location and height of the receiving antenna relative to the dynamic position, antenna height and wattage of the transmitting vessel,

b) Interference of the radio frequency transmission between the vessel and the receiving antenna, and the

c) Interference in the collection of the record originating from the vessel

a) Visual analysis of daily record byte count over a year long period

b) Verbal and email communications with U.S. Coast Guard Navigation Center personnel

Records were received from all U.S. Coast Guard NAIS terrestrial receivers.

All data records for Alaska, including those collected by NAIS receivers, have been filtered out of our data products, at the request of the Alaska Marine Data Exchange (MXAK), who own a vast majority of the receiving stations across the state of Alaska.

These data are logically consistent

The Marine Cadastre project has ended its use of the U.S. Coast Guard's 2018 Authoritative Vessel Identification System (AVIS) database to overwrite vessel attributes in AIS data distributed to the public. Beginning in 2024 the AIS Vessel Identification Database (AVID) is now used to validate and, in some cases, overwrite vessel attributes that are either null or clearly incorrect in their structure or content. These changes have resulted in an improvement to over 10 percent of the total records. The AVID was compiled in late 2023 using over 20 unlicensed and carefully vetted data sources.

Beginning with AIS broadcast point data in 2025, some small but important data updates have occurred to provide more analysis-ready data to users. These updates include:

- Adopting the Zstandard (.zst) compression format for daily download files

- Adjustments to the case and format of file names

- Changes to the case and format of field names, along with the shortening of the 'transceiver' field name

- A change in naming and swap of order for the longitude and latitude fields

- The removal of sentinel and out-of-range values, which are now reported as null values

- Updates to the format of some fields to support more accurate data types

- Decreasing the scale of the Heading, Length, and Width fields to include only whole numbers

- Removal of rare and random invalid characters from the start of records

- Removal of records with invalid MMSI values, based on length