1 - NGA

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donolt y ●xposuro cuw*See
charsctorlstlc curve.
“’- - MIL-HDBK-850
dendty-1. (photography) A measure of me
degree of blackening of an exposed film, plate,
or papar after developmam, or of the dlracr
Image (In fhe case of a prlnfouf matertal). It IS
defined slrfctfy as the Iogartthm of the optical
crpacky, where the opacity is the mtii of Ihe
incident to fhe transmitted (or reftacfed) Iiihl. If
variaa wtfh fhe use of scattered or specular fight.
See also chamcferlatlc curve; contraat. 2.
(catiogmphy) The amount of detail shmvn on a
map Or Chaff. Density varies with scale and fhe
nature of tha araa being cmrtpiled. 3,
(surveying) The number of control points In a
given survey or area.
Department of Defenee lltrrarlea-Those
Depafiment of Defansa Iiiraries designated es
responsible for maintaining files and prov!ding
library servkes ratalad 10 specific MC&G data of
mmmon DoD interest, and designated as the
primary IIbrary of that dala wilh the responsibility
for providing service Ior all authorized agencies.
Department of Defense World Geodetic
System (DoD WGS)--A unified wortd datum
based on a cornbhation of all available
astrogeodetic, gravimetric, and safelfiie tracking
obeervalione. Previous World Gaodelic Systems
wera WGS 59, WGS 60, WGS 66, and WGS
72. The currem sysfem is WGS S4. Ttra syslem
is reviati as new geodetic, gravimetric, and
salellfte data materials change the currently
aczepted values.
dapamrre-1. (plane surveying) The
orthogmphic projection of a Iina on an easf-wesf
axis of reference. The depariure of a fine is the
difference of the meridian distances or
kmgitudas of the ends of the line. It k east or
positive, and aometirnes termed lhe eaatlng,
for a line whose azimuth or bearing Is in the
norfheaet or southeast quadrant; it is wesf or
negetlve, and eomef)mes temxad lhe waef Ing,
for a tine whose azimuth or baaring is in the
notlhwest or southwest quadrant. Also caffad
Iongftude dlffererrca. 2. (navlgaflon) The
dkfanca between two meridians at any given
parallal of Iattiuda, expressad in linear units,
usually nautical miles; fhe distance to Ihe easl
or wesl made good by a crafl In proceeding
horn one point to another.
ttependanf reeurvey-A resurvey for
accomplishing a restoration based on fhe
67
orfginal condilbne according to the records. The
dependarrl resurvey is made, Wt. by Identifying
existing corners and other recognised and
acceptable peims of control of the original
survey and, second, by restoring the MISSIIW
comers by proportionate maaauremanfa In
harmony with the original aurvay. This ~ of
raaurvey is used where Ihere Ls a fair agreement
berwean the conditions on the ground and the
racorda of tha original survey. Titles, areas, and
descriptions should remain um5tan@. See
ako Independent roaurvey.
depraaaad pola-The celestial pole below
the horizon. Opposite of alevated pole.
depresalon angla-See angle of
depreeelon.
deprxraslon contour—A closed contour
delimiting an area of Iowar elevallon than the
surrounding terrain. Directional ticks extend from
the contour in a downhill direction.
depth contour+JCS) A line mnnecting
peints of equal depth below tfxe hydrographic
datum. Aiso called bathymetric contour;
depfh curve; isobath. . .
depth curva-See depth contour.
depth number—A numerical value placed
upon a depth contour 10 denote Its depth
relative to a given datum, Also a depth
sounding as h appaami on a chart.
depth of field—The disfance between the
points nearast and farthest hum the camera
which are imaged with acceptable sharpness.
depth of focus-The distance that the focal
piane can be moved fonvard or backward fmm
fhe poinl of exact focus, and 61111Uk’e an lMS9e
of acceptable sharpness. Also called total
range.
depth of Isoetatlc compeneatlon-The
depth babw eea level al which fhe conditbn of
equllbrlum known as Iaoataay IS complefe.
depth+JCS) The vartical dletenca fmm the
plane of fhe hydrogrsphlc delum to the bad of
the sea, lake, or river.
dascerxrllng node-The palm at whkh a
planat, planefold, or comet crusaes the acllptlc
from norlh to south, or a aalellite crosses the