MarineCadastre (NOAA AIS)

MarineCadastre is a free, open U.S. government data hub for marine and coastal spatial data, catalogued for its publication of Automatic Identification System (AIS) vessel-tracking data. Its web presence, the Marine Cadastre Hub, is served at marinecadastre.gov and hub.marinecadastre.gov^[1].

AIS is the international ship-tracking standard under which vessels broadcast their identity, position, course, and speed over VHF radio; the data is collected by shore stations and, since the mid-2000s, by satellites^[2]. Open archives of this telemetry, such as MarineCadastre's, are used in vessel traffic studies, maritime security, and research on shipping activity.

What It Does

The Marine Cadastre Hub serves as an online portal for U.S. marine cadastre data, a domain that includes vessel movement records derived from AIS alongside coastal and ocean spatial datasets^[1]. The resource is offered free of charge as government open data.

Data And Methodology

AIS is an automatic tracking system that uses transponders on ships and is used by vessel traffic services. AIS equipment reports a vessel's unique identification, position, course, and speed, integrating a standardized VHF transceiver with satellite positioning receivers^[2].

Under the International Maritime Organization's SOLAS convention, AIS must be fitted aboard international voyaging ships of 300 or more gross tonnage and all passenger ships regardless of size. Signals are collected terrestrially, with a line-of-sight range of roughly 10 to 20 nautical miles from shore stations, and from space by low Earth orbit satellites, which augment but do not replace terrestrial reception^[2].

Buyers And Use Cases

AIS data supports collision avoidance, fishing fleet monitoring, maritime security and domain awareness, search and rescue, and accident investigation^[2]. Analysts also use AIS archives to study port congestion, trade flows, and vessel behavior; Wikipedia's overview notes applications ranging from ocean current estimation to the detection of sanctions evasion through AIS spoofing or transceiver switch-offs^[2].

Because MarineCadastre distributes this data freely, it is commonly used where a no-cost historical record of U.S.-waters vessel movements is sufficient, complementing commercial AIS vendors.

Landscape

Commercial providers aggregate global AIS from satellite and shore-based receivers and sell real-time feeds and archive access, including satellite operators such as exactEarth, ORBCOMM, Spire Global, and HawkEye 360^[2]. MarineCadastre occupies the open, government-published end of this spectrum. It sits alongside other U.S. federal open-data resources such as NOAA NCEI and SEC EDGAR.

Delivery And Pricing

The hub is a web application at hub.marinecadastre.gov; the site renders content dynamically and has been captured 1,851 times by the Internet Archive's Wayback Machine as of August 2026^[3]. No paid tiers are associated with the government hub.