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orientation, the operalion of bringing the
model datum parallel to a relerence plane,
usually the iabletop of the stereoplotlirrg
instrument. Also called horlzontallzlng
the modal; Ievellng the model. S e e
also aerolevellng; oriermatlon,
delhifion 7.
laval-A partition within an MC&G data
WbIYmuP that is an aggregation of data
elements distinguishable by data
chsractaristics (e.g, resolution, scale,
accuracy).
Ilbrary attribute—(dlgltal mapping)
Properties of a Iiirary. These propartiea are
comalned in the Library Header Table, the
Library Attribute Table, and olher tables
related to them.
Ilbrsry negallve mold—A negative mold
which has been esiended to a size
compa!lble with the printed plastic map and
forming equipment, and which is kepl in file
lor subsequem castings.
Ilbrary-(digital mapping) A collection of
Covarages contained wi!hin a specilied
spatial errtem. all of which share a single
coordinate system and scale and have a
wmmon lhematic definition.
llbraIlorr-A real or apparem osclllamry
motion, particularly the apparent oscillation
of Ihe Moon, which resulks in more than
half of the Moon’s surface being revaaled
to an observer on lhe Earlh, even though
Iha same aide of the Moon is always
toward the Earih because the Moon’s
periods of rotation and revolution are the
same.
lllt—See selecflon ovarley.
Ilmbl. The graduated curved part of an
instrument for measuring angles, as that
pars 01 a marine sexlanl carrying the
altitude scale, or arc. 2. The circuiar outer
edge of a celestial body. See also lower
Ilmb; upper limb.
Ilmlt of rellable pholo coverage—A label
placed along a dashed line separating
reliable photo compilation trom map
Computation on a chart. The Iabei is always
placed on the photo compilation side of the
Iimlf line.
MIL-HDBK-850
143
line copy—Any wpy suitable for
reproduction withoul using a screen. Copy
mmposed ot lines as dk.tinguished horn
wntirwous tone copy.
Ilne of levele-A continuous series of
measured differences 01 elevation. The
indtitiual measured differences may be
Singla observations in Ihe case of single-run
leveling or fhe means of repeatad
obsewat”ons ifl the case 01 double-Nfl
Iavaling.
Ilrre of noda*The straight line wnnectirrg
lhe two points of inlersaction of the Scfiplic
with the orbit of a planet, plarsetoid or
wmet: or the line of irrlereecfion of Ihe
planes of the orbit of a satellite and the
aquator of its primary.
Ilne of posltlon-A line indicating a series
of possible positions, determined by
observation or measurement.
line of slghl—1. The straighl line between
two points. This line is in the direction of a
great circle. but does not follow the
cuwature cd the Earth. 2. The line
exlending from an instrument along which
distant objects are seen, when viewed with
a telescope or olher sighting device. Afso
called almlng ilne. 3. (optics) See Ilne
of collimation.
Ilne of soundlnge—A series of soundings
obtained by a vessel underway, Usually at
regular intewals.
Ilne patterrt-A photographic negative
wntaining parallel lines of equal-sized
widths, which are equaily epaced. Line
patterns are used for printing tones of a
color or to present a pattern of coverage for
a chart feature. Sea also area patlern
screen.
line rod—See range rod.
line thlnnlng (generalization)-1.
(vector) Reducing the quantity of
coordinates necessary to pmray tha basic
shapa at a feature by using a aerias of
rules. 2. (rasier) Process wheraby a
finear Ieature is represented in a grid by a
wntinuous series of cells, each 01 which
touches along its sides and comers, no
more fhan two other cells belonging lo the