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determine the meridian altitude.
●xmorldlan obaarvatlon-Measurement of
the attitude of a celestial body near me celestial
mertdiafl 01 the observer, for conversion to a
mer’idan altitude; or the altitude so measured.
●xperlanca radar pradlctlon—The
determination of size, shape, and relative
intensity of radar returns and a determination of
radar shadow and no-ratum araas based
primarily on the radar knowledge and
experience of the Individual making the
prediction ralher than on proven formulas,
fmvver tables, or graphs. Also called artwork
prediction.
MIL-HDBK-850
experimental map—A sample ot a new map
product prepared either to obtain user approval
of the adequacy of content and symbolization or
to dkclose any problems which may occur in the
various production stages. Also called
prototypa. See also pilot sheet.
explamanl—The difference between an angle
and 360”.
axploltatlon—The process of oblaining usaole
data lrom imageV.
exploratory suway—A survey execuled for
the purpose of obtaining generat Information
concerning areas about which such inlormalion
is rrol a matter of rewrd.
exposure Interval-The time required
between successive exposures 01 a series of
photographs for the purpose of obtaining
dasired forward lap.
exposure atatlon—See alr station.
exposure tlm%The time during which a
Iighf-sensitive material is subjected to the action
Of light.
●xpoaura-1. The total quanlity of fight
received per unit area on a sansilized plate or
tilm; may be expressed as the product of the
Iighl intensity and the exposure time. 2. The act
ot axposiW a Iigh!-sensitive material to a light
source. 3. One individual picfure 01 a strip 01
photographa, ueually called frame.
extended color—See bleed.
exlenalon of conlrol—Execution of
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addfiional control from exiatlng control by any
method.
axtanalon—1. (surveying) See
prolongation, 2, (photogrammetry)
Extending existing cmlrol Irom a controlled area
info an area wilhoq comrol. The term is usually
ftsrlher qualified as horizontal or vetlical
according to the primary purposa. Also called
horizontal axtenalon; horizontal/vertical
extension; vartlcal exfeneion. See also
centilaver extenalon.
exterior orientation—The determining
(analytically or In a photogrammetric Inatrunrenf)
of the position of the camera Stalin and the
attitude of the taking camera al the Inefam of
axpxiure. In stereoscopic Instrument practice,
exterior orientation is divided into two patiS,
relative and absolute orientat”bn. Also called
outer orlantatlon. See also reeectlon,
definition 3.
exterior perepectlve center—See
perapectlve center.
exterior to e cuwa-Any area adjacent to a
curve Iying toward ils Convax side, the area MI
included wlfhin the circle of which the curve is
pad of fhe circumference.
external distance-The distence from the
vertax O! a circular curve to the middle point of
the curve.
axternal arror—The repealability of a
measurement with any condition extraneous to
!ha measuring method itself changed;
contrasted to internal error. See alao standard
error.
extra forealght-(leveling) The rod raading
made at an inSttUmeM station In a fine of Ievek
and on a leveling rod standing on a bench mark
or another point not In the @XIflfWOUa WIe of
levels. In spirit leveling fhere may be one or
more extra foresight from a single instrument
station or setup, but Ihere can be only one
backsight and one foresight from any one
instrument station.
exfrapolatlon—The process of estimating the
value of a quantity beyond the limits of krmwn
values by assuming that the rate or system of
change between the last few known vafues
continues.
eye baaa—See Interocular dlatance.