1 - NGA

ntaans d wttidr dslmaes on the map, chart, or
phonograph may be measured in terms of
ground dtincas. Al= calisd bar scala. See
also Scale.
graphical mdlnl trtangulaUon-A rsdiil
triangufati perfmmad by other thsn SMwi
msena. A radial trisngufstion is aasurrmcf to be
rrmda *h prfrrc@ points as radiil o@ere
unfasa the defiiitiwe term designates olherwise
(as, for esanrpfs, nadir-point ttingufatiorr or
nadii-point plot emf iaosarter trisrrgulation or
lsocarrter plot, and ruidit-poirrt efoffed-tamplme
pki, eic.).
graphlcel rectlfJcstlon-Any rectifiiat”mn
technique etrpfoying a grephw method fer
determining the solution as mntraefsd with
rnechsnicsl technques. See also paper-strip
method.
gmphlc~JCS) Any and ell products of the
cartogmphc ad phol~rarnrrwtric art. A grephio
rney be either a msp, chart, mosaic, or even e
film str@ that was producsd using certogrephii
technques.
graticulo-1. A netwmrk of Iinss mprassnling
parsllsts of ielitude wrd rneridicms of longitude
forming a msp projection. See also fictitious
gratlculo. 2. A scsle at the focel plane of an
optiicl instrument to aid in the meesuremen! of
objects. See e.tsa retlch.
Gmvatf I’vallng rod-A speaking rod,
merked with rectsnglas ssch 0.01 foot high, the
ractangks at the 0.1 of foot tAng bnger and
those at the 0.5 being identiied by dots.
Gmvstf Iavof-A dunpy level with the spirit
level mcunied on top of a short telescope tube
having a large object glass. Later msde with
Wysa.
Qrevar—See scrfber.
gravkneter (gravity mater)-A n
a~iemmefer designed to measure relative
dfle-s in the accalerstion due to greviiy at
different Iomticms.
gmvlmatrlc coordlnatas-See ●stronomic
coordlnatas.
grsvlmatrlc detum orlontetlon—
Adjustment ef the eifipedd of reference for a
rticular geodetic datum so lfral the differences
&vreen the gmvimetris and estrogeodetic
MIL-HDBK-a50
109
deftect”km compenerrts and geoidsl undufstions
am minimized.
gmvlmatric deffectlon~ deflection of the
vertical determined by methods d gmvintafric
geodesy.
gravlmetrlc goodosy-The science that
utifiuea maesumments and cfreracferktii of the
Earth’s grav”kyfmld as well es thaotiee ragatdii
thw fiefd to deduce the shepe d the Esrth and
in c=xbkmkm with arc meeeurernsmm, the
Eatth’s size. AlfuJ called physlcel geodesy.
gmvlmotrlc geold-h eppmximetien to the
geoid ss determined from gnwity observation.
gmvlmstrlc map-A map on which contour
lines are used to represent points at wtkh the
esceleralion of grevity is equsi.
gravlmetrlc survey-A swrvey made to
determine the acceleration of gravity st vsrious
places cm the Earth’s surface.
gravlmotrlc undulatlona—Separations
bstween s grravimetrically determined geoid and
a refweme elliiso”d d specified flattening.
gravitational constant-see constant of
gravitation.
gravitational disturbtwrce-See gravity
disturbance.
gmvltatlonal flattening—llwt mtio of the
dfierence between the poiar and equetorisf
ncwrnal gmvifies to the equetcwial normal gmvity.
Aloe called grmrlty flattening.
gravitational gradient—The chenge in the
grevity per unil distarrca.
gravltatlonsl hermonlc-The spheriaal
herrnmk used in a~mxirrwting the
grmritetionel field of the Earth. Sea ekw gravity
field of the Earth; coctorlel harmonica:
sphorlcal tmrmonlcs; tessaral
harmonics; zonal harmonlco.
gravitational perturbations- Perturbations
caused ty body foroes due to rro~herkal
Ierrestrisl effscts, Iurricofar efkt, tides, and the
effect of refetivity .
gravltntlonal potantlal-1. The potential
associated with the Ioma of gmvitet’km arising