1 - NGA

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podstk kt\tude-The angle whiih the
norrnai et n point on the referenoe spheroid
rrmkae wffh the pfsne of the geodetic aqueier.
Geodatii latitudes are reckoned from ttw
Equator, but in the horisc+wsl confrd survey d
the United States they are ~ed from ths
fatifude of afafiin Mearka Ranch as pmecrbad
in the North Amarican detum d 1927. The new
North American dsfum of 19S3 wifl be Emt&
resee centered. A gecxfel”c fstiftie differs hum
the c==Pondiw ~~ fstitude b the
amount d the rnerfdbn coqmnanf of tL
daffecikm of the varfbsl, Aim cafied
topographlml Iatltudo.
MIL-HDBK-850
geodetic kavaflng-spirif Ievefing of a h~h
order of smu~cy, uerzslfy azfandad over fsrga
arms, to fumrsh amurate vertkef control as e
ksis for the mnfrd in the vertical dimension for
all surveying and mapping epsretkms. Spirit
Ievefing follows the gacrid and ifs associated
level surfacae tiich are irragufsr, rather fhsrr
any mathemst”wliy determined @heroid or
ellipsid and samcieted regular level surfaces.
geodetic lhm-See geodmlc Ilna.
gaodotic iongltuda-lhe angie between the
plane of the geodetic rneridiin and the plane of
sn inifisl nzerfdmn, arbh%uffy chosen. A geodetic
fongffude can be measured by the angle al the
pd. of mtsfion of the reference spheroid
between the focsf and initiil maridiins, or by the
arc C4 the geodetic equator intercepted by these
rnerWans. In the Unftsd Statae, gaodet”k
bngifudea are numbered fmm fhe maridiin of
Greenwich, but are mmpufsd fmm the maridiin
of sfatbn Meedas Ranch es prescribed in the
North Amsricsn datum of 1927. The new North
American datum of 19S3 will be Eerth-msss
centered. A geodetic bngifuda differs from the
corresponding aetmnomk fongifude by the
ernount of the prims verfid caponent c4 fhe
Iocsl daflactkm of lhe vertiil dwided by the
cosine of the fatifude. Also csrliwf geocentric
Iongl:uda.
goodotlc meridian plane-A piane that
cwrfsins the normal to the reference eliiisoid at
s dven odnt rmd the rotetion arris c4 fhe
reierencb etfipacid.
geodetic merldlen-A line on a reference
ellipseid which has the esma geodetic fongifude
et rwery pint. Also called gaographlc
meridiwr.
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geodetk pmalld-A line on the ref.smnce
SPhamid whiih tMS ihe asma @odatic hthtdn
M every point. A gsodefic panel, other ttwrr
the Equator, ie nd a geodesb (gmdatic) Ime. h
form, II m a emsfl ckcle wtmaa plsrra is psraiiaf
with the plane d the gecdafii aquetor.
gaodotb pOSftiO# pfxifkrtl d a POil’d On
the surface of the Eerth e~aaeed in terms of
gamielic Iatikde, geodetic Iengiiuda, and
geodetic hdit A ~tc Pwifii rrr@aa an
adopted geedetic datum.
gaorktlc setelllt*Any eateifide wfzma orbit
and payload render it useful for gaodalic
purposes.
gerodetlc stellar camere—A precision
Ierrastrisl csmsra, usually employing giass
plales, used to photograph ekwatsd illuminslad
objscfs against a star bsckgmund.
geodetic survey-A survey in whch the
f~ure and size d ths Esrfh is considarsd. if is
appbbfa for Large areas and tong iina.e end is
U* for the pracisa Imation of beeii points
suitabka for controlling ofhw surveys.
geod.stlc zenith-The point whare the nermsl
(to the refarenca spheroid) exfanded upward,
masts the ceieet”-1 sphere.
Geodimeter-A trsde nsme for an instrument
the! measures distance by pradce elecfrork
phesa mmparison of mcdufated light waves
vhii trsvei to a refbctor and return.
geoakctrlc sunrey-A survey to dalermine
M elactricii or resiefivii pofential of the Earth
recks.
Geographic Baae File/Dual
independent-Uap-Encoding
(GBF/DIME)-Topologicalfy structured files
developed by the Bureau of the Census whiih
serve as a relatively inespensh’e geogrephk
inforrnslion dste source. GBF/DtME fries
irduds street networfre, street addreseas,
Pofiiical boundsrfee, and msjor hydmgrsphc
faaturas. Esch street eagmant is rewasanlad
as a strsighf fine ragtudleca d its red wwfd
shape.
Geogrephk Information System (GIS)-
The generic ferm used for a system d cumpufer
software moorems and aaukzmant that is used
to acquiri, s~ore, manipulate, enafyze, and