English

A system of COOR­DINATES in a HORIZONTAL PLANE used to describe the POSITIONS of points with respect to an arbitrary ORIGIN by means of two distances perpendicular to each other. The two REFERENCE LINES at right angles to each other passing through the ORIGIN are called the coordinate axes. The distances parallel to the true (or arbitrarily assigned) north-south axis are called the ordinates, or the y coordinates. The distances parallel to the true (or arbitrarily assigned) east-west axis are called the abscissae,or the x coordinates. The north and east directions are usually taken as positive, and the south and west directions are usually taken as negative. Also referred to as plane coordinates.

A system of COORDINATES used to describe the POSITION of a point in space with respect to an arbitrarily chosen ORIGIN by means of two DIRECTIONS and one distance; i.e., the vectorial angles and radius vector magnitude.

In PHOTOGRAMMETRY the term may refer to any general three-dimensional coordinate system used to define the POSITION of a point in the object space, as distinguished from the IMAGE of the same point on a PHOTOGRAPH.

A system of POLAR COORDINATES in which the ORIGIN is the centre of a sphere and the points all lie on the surface of a sphere. The POLAR AXIS of such a system cuts the sphere at its two POLES.

The COORDINATES of any point in a strip, whether on the GROUND or actually an AIR STATION, referred to the ORIGIN and axes of the air coordinate system of the first OVERLAP.

An instrument used to plot in terms of PLANE RECTANGULAR COORDINATES. It may be an integral part of a STEREOSCOPIC PLOTTING INSTRUMENT whereby the planimetric motions (x and y) of the FLOATING MARK are plotted directly.

In PHOTOGRAMMETRY, the condition of EXPOSURE of a pair of PHOTOGRAPHS in which the two PHOTOGRAPHS lie in a common plane parallel to the AIR BASE. If the AIR BASE is horizontal, the PHOTOGRAPHS are said to be exposed in horizontal coplane.

The central or innermost part of anything. See CENTROSPHERE. In OCEANOGRAPHY, a vertical, cylindrical sample of the BOTTOM SEDIMENTS from which the nature and stratification of the BOTTOM may be determined. Also calledcore sampleor sediment core.

The tubular section of a core sampling device. Bottom sediment samples are collected either directly in the core barrel or in a plastic liner placed inside it. Also called coring (or core) tube.

A device for obtaining a CORE; a hollow tube that is driven into the ocean floor. Also called coring instrument or coring device. See CORER: HYDROPLASTIC, CORER: PISTON, PIGGOT GUN and VACUUM LEAD.

A deep sea coring device, developed at the U.S. Naval Oceanographic Office, to obtain 3 1/2-inch diameter cores up to 12 FEET in length. The barrel is constructed of high-impact grade polyvinyl chloride plastic without an inner liner. Also called polyvinyl corer.