Rhumb line.
Related Terms 
GRID RHUMB LINE
A line making the same oblique angle with all grid meridians. Grid parallels and meridians may be considered special cases of the grid rhumb line.

OBLIQUE RHUMB LINE
1. A line making the same oblique angle with all fictitious meridians of an oblique Mercator map projection. Oblique parallels and meridians may be considered special cases of the oblique rhumb line. 2. Any rhumb line, real or fictitious, making an oblique angle with its meridians. In this sense the expression is used to distinguish such rhumb lines from parallels and meridians, real or fictitious, which may be included in the expression rhumb line.

CONVERSION
Determination of the rhumb line direction of one point from another when the initial great circle direction is known, or vice versa. The difference between the two directions is the conversion angle, and is used in great circle sailing.

CONVERSION ANGLE
The angle between the rhumb line and the great circle between two points. Also called ARC TO CHORD CORREC TION.

FICTITIOUS RHUMB LINE
A line making the same oblique angle with all fictitious meridians. It may be called transverse, oblique, or grid rhumb line depending upon the type of fictitious meridian. The expression OBLIQUE RHUMB LINE applies also to any rhumb line, real or fictitious, which makes an oblique angle with its meridians; as distinguished from parallels and meridians real or fictitious, which may be consider special cases of the rhumb line. Also called FICTITIOUS RHUMB, FICTITIOUS LOXODROME, FICTI TIOUS LOXODROMIC CURVE.

MERCATOR DIRECTION
Horizontal direction of a rhumb line, expressed as angular distance from a reference direction. Also called RHUMB DIRECTION.

RHUMBLINE DISTANCE
Distance point to point along a rhumb line, usually expressed in nautical miles.

RHUMB
Short for RHUMB LINE.

RHUMBLINE SAILING
Any method of solving the various problems involv ing course, distance, difference of latitude, difference of longitude, and departure as they are related to a rhumb line.

RHUMBLINE COURSE
The direction of the rhumb line from the point of departure to the destination, expressed as the angular distance from a reference direction, usually north. Also called MERCATOR COURSE.
