A fact known from direct observation.
A premise from which conclusions are drawn.
A floating reference point, or SLDMB, used to evaluate surface currents in a body of water. Often employed by coastal search and rescue.
A fixed reference point or set of reference points which precisely define a system of measurement or a coordinate system.
To provide missing data points by using a mathematical model to extrapolate values that are outside the range of a measuring device.
An introductory statement of facts or background information.
An incentive that helps bring about a desired state. In some contexts, this can imply bribery.
The act of placing a port on a vessel's itinerary because the volume of cargo offered at that port justifies the cost of routing the vessel.