1 - NGA

MIL-HDBK-850
Croso.Country Mmmrnont MaP (cCM)- A
DMA map de@cfirrg CfOSS-CUI.MfIymobility
eafiiws tor the M-1 ts~ expressad in terms O{
GO, RESTRICTED. SLOW, VERY SLOW, and
NO GO with correaporrdirro everage speed
range pradicfkme. Open water and urban areas
are afao pmtrayed, as are ground movement
obatackas and hydrobgk hkrdrarces. Ptoducsd
at 1:50,000 and 1:250,000 ecale.
croee-coum~ movement study-A graphic
or sertes ot graphics and supporting text or
tables ponraying off-road movement conditions
for e@tic vehicles or a group of vehdea. tf ie
usually overprinted on a medium- or large-scale
topographic rrwp basa.
cross.fllgfrt photography—ShWle photographic
etr@ heving elaraoacopic overlap
behveen exposures and having e flighl direction
at right angles to that of coexistent area
coverage photography. When applied to
shoran, the Iarm hnplies that each of the crosslight
expoeurea la accompanied by remrded
ahoran distances. See also control atrlp.
CrO~.-S0CtiOtiA horizontal grid system laid
out on lhe 5r6i.-nd tor determining contours,
quantifies of earthwork, etc.. by means of
elevations of the grkl points.
crossing sn@s-The angle at which hvo lines
01 pesifiin, cxwae Iinas, etc., intersect.
crossllne glass screrrrs-See halftone
screen.
crystal clock—A device tor keeping accurate
lime. It consists essentially of a generator of
constant frequency controlled by a resonator
made of quartz crystal, with auifable methods for
pm.ducing corsfinuoua rotatiin 10 oparele time
indkxting and related mechanisms.
culmination—The position of a heavenly body
whan af h~heat apparent altitude (zenith).
Kr!own as upper Culmination; also, tor a
heavenlv bodv wftiih la comlnually above the
hortzon,’the bshbn of bwest ep~rent altitude,
known as lower culmination. CUhTtinaliOn
rscwre whan lhe body transits the iocd
meridian. See alao lower tranelt; trsmslt;
upper transit.
cultural dotalla—See culture.
cultural taaturee—See culture.
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cultura-(JCS) Featurea of lhe terrain thet
have been cmalrucfed by man. Included are
such tiems as roads, buildings, and canals:
boundary Iiies, arsi in a bread sanae, all
names and legends on a map. MO called
cultural detalla; cultural teatures; manmede
Ieaturee.
currancy review—lhe comparison of an
existing MC&G product against eoume materkil
o} later date man that trom which fha producf
was produced, for the pupae of determlrthsg
the products camency.
CUrrOnt chs1l-A map ot a watar area
depicting current speads and directions by
Cuf’renf roses, vectors, or other means.
current CYCIS-A complete sel of Iidal currenl
conditions, as fhose occurring during a tidal day,
lunar month, or Metonic cycle.
current diagram—A graphic presentation
showing the speed of the tiood and abb
currents and the times of slack and strenglh
ovar a conekterable stretch of the channel of a
tidal waterway. The fimes being referred 10 as
tide or wrrem phases at some relarersca
stations.
current meter—A device for determining the
vabcify of fbwing waler by ascertaining the
speed at which a stream of water rotates a vane
or wheel.
current rose-A graphic presentation of
w rrents for speciiied areas, rsliliilng armwa at
the cardinal and inlercardlnal compass pOinlS to
show the dhecfion toward whch the prevailing
currenf flows and the percent frequency of set
for a given period of time The arrows on some
presentatbns may be further subdivided (by
lhkkness or pattern) to designate categories ot
current speeds.
curvature correction—l. (as fronomy) A
correction applied to the mean of a series of
observat”nns on a star or planet to take account
of Ihe d!vargence to the 6pp6reM pelh ot the
star or planet Imm a straighl line. 2. (gaodesy)
The correction appfied In some geodetk work fo
fake account of the divergence 01 the surface ot
the Earth (spheroid) horn a plane. In geodetic
spirll Ieveting, the eflecte of curvalure and of
efmospheric refraction are mnsldered together,
and fables have been prepared trom which
combined corrections can be taken.