# ORTHOGONAL

Right angled, rectangular. PROJECTION.

## Related Terms

### LUMINANCE

In a given direction, at a point on the surface of a source or receptor, or at a point on the path of a beam, the quotient of the luminous flux leaving, arriving at, or passing through an element of surface at this point and propagated in directions defined by an elementary cone containing the given directions, by the product of the solid angle of the cone and the area of the orthogonal projection of the element of surface on a plane perpendicular to the given direction. The derived unit of luminance in the International System of Units is the CANDELA PER SQUARE METER.

### COMPONENT

1. The part of a tidal force of tidal current velocity which, by resolution into orthogonal vectors, is found to act in a specified direction. 2. One of the parts into which a vector quantity can be divided. Fo

### DEGREE-OF-FREEDOM

The number of orthogonal axes of a gyroscope about which the spin axis is free to rotate, the spin axis freedom not being counted. This is not a universal convention. For example, the free gyro is frequently referred to as a three-degree-of-freedom gyro, the spin axis being counted.

### ORTHOGRAPHIC MAP PROJECTION

A perspective azimuthal projection in which the projecting lines, emanating from a point at infinity, are perpendicular to a tangent plane. The projection is used chiefly in navigational astronomy for inter converting coordinates of the celestial equator and horizon systems. Also called ORTHOGONAL PROJECTION.

### PARAMETER

1. A quantity which remains constant within the limits of a given case or situation. 2. One of the components into which a craft’s magnetic field is assumed to be resolved for the purpose of compass adjustment. The field caused by permanent magnetism is resolved into orthogonal components or parameters: Parameter P, Parameter Q, and Parameter R. The field caused by induced magnetism is resolved into that magnetism induced in 9 imaginary soft iron bars or rods. With respect to the axis of a craft, these parameters lie in a fore-and-aft direction, an athwart ships direction, and in a vertical direction.

### SINGLE-DEGREE-OF-FREEDOM GYRO

A gyroscope, the spin axis of which is free to rotate about one of the orthogonal axes, the spin axis not being counted.

### TWO-DEGREE-OF-FREEDOM GYRO

A gyroscope the spin axis of which is free to rotate about two orthogonal axes, not counting the spin axis.

### DEGREE OF FREEDOM

1. Any one of the number of ways in which the space configuration of a mechanical system may change. 2. Of a gyro, the number of orthogonal axes about which the spin axis is free to rotate, the spin axis freedom not being counted; this is not a universal convention; for example, the free gyro is frequently referred to as a three-degree-of-freedom gyro, the spin axis being counted.

### Related questions

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