1 - NGA

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meridian through 24 hours; Greenwich hcur
s@e d the VWIMd F@nOX. =W- ~ t“~
units.
Grwenwlch time-llna basal upon the
GM* marktisn as mferenm, as mnfrssed
*thstbaa edWor reMof - meridian.
grid smplltud~rrpfiiude relative to grid
east or wwt. See also smplltudo.
grfd azhntrth-The angle in the plans of
P@tibn rnaaaumd cbdrwbe between a
straight fiie and the central rneridiin of a ptane
mcfingufar coordhale system.
grid fmering-(JCS) searing measured ftom
grid north.
MIL-HDBK-850
grfd computation-The detamrinaticm fmm
a set of fables derived from formulas, of the true
shape and dlmene’brrs of a grid, for the purpose
of constructing such a grfd. The grid is
mstherrmlimlly coordinated with its related map
projacfiom they are usually compulsd
corrW-renfty
grid convergence-(JCS) The horizontal
angle at a place between Irue north and gr”d
ninth. It is pmporliinsl to the longitude
difference between the pfsca and the central
meridiin. See elsa convcrgenca.
grid coordinate system-(JCS) A pfane
rectangular oeordhale system ususlly bessd on,
end rnathematbally adjusted to, a map
prc@fion in order that gwgraphic p.aeifibns
(fatitudes and longitudes) msY be ras~y
tmrraformed into plane coordhslea and the
rnmpUl~fiifrS refafing 10 them may be msde by
the ordmsry mahrts of plane aurvayirrg.
grid coordhratea-(JCS) Coordheles of a
grid mordinste system to wtrich numbers ardor
letters ●m assigned for use in designating e
point on e gr)dded map, photograph, or chart.
Sss also coordlneten.
grid daaIlnatlon-The angular difference in
dirscfion between grid rrorlh end hue north. II is
measured ess or west fmm true north, Also
called declination of grid north;
gls.msnt.
grid dhectlor@-foffxonfsJ dimctkin expreeaed
as angular distance fmm grid north.
112
grid dlstanm-See grid Iarrgfh.
grid equMOr-A fine pwpendhdar 10 a prime
grid fnaridian, et the tiln.
grid lntsrvaf-(JCS) The d~tsiwe represented
be4ween the fines d a grid.
grid Inverse-1’he computatbn d grid length
and gr”idazimuths from grid coodinsks.
grid JunctIona-Those Iirms daikreeting the
jokringoftwoorrn ora@daY*emsmam$Por
chart.
grid Iatltuds-+ngular diatarrce from a grid
equator. Sea else flctftloua Iatltudo.
grid fangth-The dis$rmce between tw pdnts
obtained by amputation from grid oocdrrdee
of the points. It dtiera from the geodetic kengfh
by the amount d a small correction besad on
the acsfe factor for Ihs Iins. Also calfed grid
dlstanca.
grid lln@-CXre of the lines d e grid.
grid longftude-Angular distance bstween e
prime grid meridiin and sny given grid meridiin.
See also ?ictltlous Iongltudo.
grid magnotlc ●ngle-(JCS) Angular
dtiere~e in diracfbn between grid mxfh and
myr9nsfm nofih. It is rmmsured east or wasr fmrn
gnd north. Afao called grlvatlon; grid
varlatlon.
grid merldlatine of the grid fines
aslending in a grid north-south dkcfion. The
reference grid meridiin is called prima grid
marldlan. In polar mgicms the prims grid
msridlan is usually the 180”4” geographic
meriden. See also flctltkmm rn.rldlan.
grid mathod+pktogremmetry) A method of
pbrting ~il from oMque photogmp~ fV
SWdW@sm9 e Wmpact&e C4 e map grid on a
photograph ❑nd Imnsferring the detail by eye,
thst is, by using the corr-ng lines of the
msp grid and itrl pemp=tw e rmi plemment
guides. See elm parspectlvs grid.
grid north-(JCS) The rrorfherfy or zem
direction Indutad by the grid datum of
dirsct.ksrsl reference.