English

A relatively large area of free navigable water in an ice-encumbered SEA. In U.S. terminology, an area of SEA with less than one-tenth ICE CONCENTRATION.

A recording device designed to measure by revolutions of a small wheel, continuous linear di­stances on a MAP. Used in measuring the length of SHORELINE by closely following all the INDENTATIONS and sinuosities of the SHORE.

The situation of two periodic quantities differing by half a CYCLE. In ASTRONOMY, the situation of two CELESTIAL BODIES having either CELESTIAL LONGITUDES or sidereal HOUR ANGLES differing by 180°. The term is usually used only in relation to the position of a SUPERIOR PLANET or the MOON with reference to the SUN.

The point of intersection of lines which represent within the LENS those RAYS whose emer­gent directions are parallel to their respective inci­dent directions. This point lies on the optical axis.

A surface, usually of glass, ground and polished plane within a fraction of a WAVE LENGTH of light. An optical element or glass blank with an opti­cal flat is used to test the flatness of other surfa­ces.

A bottom sediment sampling device capable of obtaining as much as 1/2 cubic foot of sample from the ocean floor. Named for its likeness to an orange that has its peel quartered.

The path of a body or particle under the influ­ence of a gravitational or other force. For instance, the orbit of a CELESTIAL BODY is its path relative to another body around which it revol­ves. In water waves, the path of a water particle affected by the wave motion.

Member States promote economic growth, employ­ment, and improved standards of living for a sound and harmonious development of world economy.

The act of establishing the correct rela­tionship in direction with reference to the POINTS of the COMPASS. The state of being in correct relati­onship in direction with reference to the POINTS of the COMPASS. A MAP is in orientation when the map SYMBOLS are parallel with their corresponding ground features. A PHOTO­GRAPH is in orientation when it correctly pre­sents the perspective view of the ground or when IMAGES on the PHOTOGRAPH appear in the same direction from the point of observation as do the corresponding map sym­bols. See ORIENTATION OF PLANE TABLE, ORIENTATION OF SURVEYING INSTRUMENT, ORIENTATION: PHOTOGRAM­METRIC.

In PHOTOGRAMMETRY, the scaling, levelling, and ORIENTATION to GROUND CONTROL (in a photo­grammetric instrument) of a relatively oriented stereo­scopic model or group of models.