Glossary#
AIS#
Automatic Identification Systems. A tracking system used on ships and by vessel traffic services for identifying and locating vessels by electronically exchanging data with other nearby ships and AIS Base stations.
AOI (Area of Interest)#
A specific geographical area to monitor for vessel activity.
Attribution#
Data automatically attributed to each vessel by Theia. The user can manually alter this.
Bunkering#
Ship-to-ship activity; when two ships are berthed alongside each other. Reasons for this can include the transfer of products.
Coordinates#
A set of values that determine a specific location on a map. In the context of Theia, coordinates are used to specify the location of a vessel or an Area of Interest (AOI). They are usually given as a pair of latitude and longitude values.
Theia’s tiled web map (slippy map), powered by Leaflet, uses the EPSG:3857 projection (aka Web Mercator). The coordinates visible in the top left when hovering over the map, or any other coordinates in Theia, are WGS84 coordinates.
Dark vessels#
Dark vessels refer to maritime vessels that do not transpond their locations, often to avoid detection for various reasons. These vessels can be involved in illegal, unreported, and unregulated (IUU) fishing, illicit ship-to-ship transfers, and vessel spoofing.
Monitoring dark vessels provides valuable insights for companies relying on transparent maritime commodity flows and hedge funds invested in the energy industry.
ETA#
Estimated time of arrival.
Extended Path#
The path a vessel has taken over a certain period.
IMO#
International Maritime Organization number. A unique number consisting of seven digits. Used as an identifier for ships and for the enhancement of maritime safety, pollution prevention, and the prevention of maritime fraud. Remains unchanged throughout the ship’s life, regardless of changes in the ship’s owner, country of registry, or name.
Light vessels#
Light vessels are vessels that were imaged while their AIS was active.
These vessels are typically compliant with international maritime laws and are transparent about their location and activities.
MMSI#
The Maritime Mobile Service Identity (MMSI) is a unique nine-digit number assigned to a maritime object, effectively serving as its international maritime telephone number. This identifier is issued by the object’s current flag state and changes whenever the object is re-flagged.
A maritime object can be a vessel, fixed offshore installation, mobile unit, maritime aircraft, coast station, and more.
Nautical Mile#
A unit of length used in air, marine, and space navigation, and for the definition of territorial waters. It is defined as exactly 1,852 meters (6,076 feet; 1.151 miles). The derived unit of speed is the knot, one nautical mile per hour.
Object ID#
A number associated with a satellite image.
Spoofing#
A vessel using its AIS system to purposely deceive authorities by transmitting a false position instead of its true location.
Synmax Ship ID#
A unique ID assigned to a vessel by Synmax.
Unattributed vessels#
Vessels that were imaged while their AIS was turned off and have not been attributed.
These vessels may not necessarily be involved in illicit activities but represent a category of vessels that are not immediately identifiable due to the lack of AIS data.
Vessel Draft#
The distance between the waterline and the deepest point of the boat. This is important to know as changes in draft measurements can indicate product being loaded or unloaded from a vessel.