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Eng ID Term Definition
2181
gyro sextant
See SEXTANT.
2182
hachures
Short lines drawn on a CHART or MAP for representing RELIEF. These lines are drawn in the direction of the SLOPE and intensified on the shad... more
Short lines drawn on a CHART or MAP for representing RELIEF. These lines are drawn in the direction of the SLOPE and intensified on the shaded side of the feature assuming the area is illuminated from the north-west. Unlike the CONTOUR LINES, they give no indication of the actual HEIGHT of LAND above SEA LEVEL. See also HILL SHADING.
2183
hack watch
See WATCH.
2184
hail
PRECIPITATION of small balls or pieces of ICE (HAILSTONES) with a diameter ranging from 5 to 50 mm (0.2 to 2.0 in) or sometimes more, fallin... more
PRECIPITATION of small balls or pieces of ICE (HAILSTONES) with a diameter ranging from 5 to 50 mm (0.2 to 2.0 in) or sometimes more, falling either separately or agglomerated into irregular lumps.
2185
hailstone
Globule or piece of ICE, with a diameter varying between 5 and 50 mm or even more, the fall of which constitutes HAIL. Hailstones consist al... more
Globule or piece of ICE, with a diameter varying between 5 and 50 mm or even more, the fall of which constitutes HAIL. Hailstones consist almost entirely of transparent ICE, or of a series of LAYERS of transparent ICE with a thickness of at least 1 mm, alternating with translucent LAYERS.
2186
halation
In PHOTOGRAPHY, a spreading of a photogra­phic IMAGE beyond its proper boundaries, due especially to REFLECTION from the side of the film or... more
In PHOTOGRAPHY, a spreading of a photogra­phic IMAGE beyond its proper boundaries, due especially to REFLECTION from the side of the film or plate support opposite to that on which the EMULSION is coated. Par­ticularly noticeable in PHOTOGRAPHS of bright objects against a darker background.
2187
half byte
4 bits of a 8 BIT BYTE; usually used to encode the figures 0....9.
2188
half convergency
See ARC TO CHORD CORRECTION.
2189
half tide
See TIDE.
2190
half tide level
The LEVEL midway between MEAN HIGH WATER and MEAN LOW WATER. It may differ slightly from MEAN SEA LEVEL. Also called mean tide level.
2191
halftone
In PHOTOGRAPHY or printing, a technique in which the solid IMAGE is broken up by the use of a screen into evenly spaced dots of equal densit... more
In PHOTOGRAPHY or printing, a technique in which the solid IMAGE is broken up by the use of a screen into evenly spaced dots of equal density but of varying size. This gives an illusion of con­tinuous tone.
2192
halo (solar, lunar)
Group of optical PHENOMENA, in the form of rings, arcs, pillars or bright spots, produced by the REFRACTION or REFLECTION of light by ice cr... more
Group of optical PHENOMENA, in the form of rings, arcs, pillars or bright spots, produced by the REFRACTION or REFLECTION of light by ice cry­stals suspended in the ATMOSPHERE (cirriform CLOUDS, ICE FOG, etc.).
2193
halo: large (halo of 46°)
HALO much less frequent and always less luminous than the SMALL HALO. It comprises a faintly luminous ring centered on the SUN or MOON and h... more
HALO much less frequent and always less luminous than the SMALL HALO. It comprises a faintly luminous ring centered on the SUN or MOON and has an apparent radius of 46°.
2194
halo: small (halo of 22°)
White, or mostly white, luminous ring of 22° radius with the luminary at its centre. The small halo shows a faint red fringe on the inside a... more
White, or mostly white, luminous ring of 22° radius with the luminary at its centre. The small halo shows a faint red fringe on the inside and, in some rare cases, a violet fringe on the outside. The portion of the sky inside the ring is conspicuously darker than the rest of the sky.
2195
halocline
A vertical GRADIENT of salinity (which is usually positive) in some LAYER of the body of water, which is appreciably greater than the GRADIE... more
A vertical GRADIENT of salinity (which is usually positive) in some LAYER of the body of water, which is appreciably greater than the GRADIENTS above and below it.
2196
hand lead
See LEAD.
2197
hand lead sounding
See SOUNDING.
2198
hanging compass
See COMPASS.
2199
hanging traverse
See TRAVERSE: OPEN.
2200
harbour (or harbor)
A natural or artificially improv­ed body of water providing protection for vessels, and generally ANCHORAGE and docking facilities. See also... more
A natural or artificially improv­ed body of water providing protection for vessels, and generally ANCHORAGE and docking facilities. See also PORT.