1 - NGA

., .,. !,-
fix—A relatively accurate posilion determined
without reference to any former posilion, from
terrestrial, electronic, or astronomic data Also,
the poirxf Ihus established.
flare triangulation-A method of
friartgufafion In which ahrrtrltaneous observations
are made on parachute flares. This method ia
used for extendi~ triangulation over lines too
bng Io be observed by ordinary methods.
flash rspparatua-An auxUlaW apparatus
used in timhxg a pendulum during obsen’aliona
for intensity of gravity.
ffaxrh plata-See callbraflon plate.
flat model—Any spatial model which is
capable of being leveled. See also warped
model.
flat stock-1. Charls or maps which are not
folded and kept Ior filllng ollicial and sales
orders. 2. Flat sheets of map paper as opposed
to roll paper.
flat tlnf screen-See dot screen.
. . . .
MIL-HDBK-850
Instrument. 2. (steraoscopy) me alfemafe
bllnking of the eyes and mentally com@ring Ihe
appearance of images in a stereoscopic pair to
determine diflererces between the two photos.
flight altltuda-The verfkaf disfance above a
givan datum, usuaUy mean sea level, of an
aircraft in flight.
IIlght block—An adjustable unit of
photographic coverage cmrairdi~ of overfepping
strips of phonography. A minimum size block
consists of at least three overiappiig ffiiht atrips.
flight cherf-See route chart, definition 2.
fllght Information and alr facllltles
data-Data concerning airfields and aeapfane
atalions and retated information required for the
operation of aircraft.
fllght Ilne apaclrrg-The distance betwaen
adjacent tracks in a series of parallel aerial
photographic flight strips.
fllght lhxa-(JCS) In air photographic
reconnaissance, the prescribed ground pafh
over which an air vehicle moves during, the , .,
execution ot its crlroto miss”km.
flattening (of the Earth)-The ratio of fhe
difference between the equatorial and polar radii fllght map-A map on which ara indicated tha
of the Earth (semimajor and semiminor axea of DroIJoaed Iines 01 Worst ancUor oosifions of
the apharoid) to tts equatorial radius (semimajor
axis). Alao called compreaeion; elllptlclty of
the apharofd. See also eccenttlclty of
alltpae: eccentricity or apharold of
revolution; elllptlclty of elliprsa.
flat—1. (Iiihography) An assembly of
photographic negatives or positives on
goldenrod papar or vinyl acetate tor contact
exposure with a sensitized metal press plate
May contain Ulustralbns as well as text. See
also key flat; layout. 2. (photography)
Lacking in contrast. 3. (optba) See opttcal
flat.
flexura-1. (pendulum) The banding of a
ewinging pendulum, due to its lads of pertecf
rfgidity. 2. (pendulum eupporf) The forced
movament of a parrdulum aupporf caused by
the mofion of ffre swinging pendulum.
fllckar method—1. The alternate projection
of corresponding photographic Imagas onto a
tracing table platen or projection screen, or into
fhe optical frain of a photogrammetric
&x@sure stations. @fht data are piotred on the
best available map 01 the area. Generally used
[or planning purposes.
fllght etrip-A succession of overlapping aerial
photographs Iaken along a single murse. Atao
called atrlp.
fllpplng—The act of superimposing and
mmparing identical areas of two overfapphxg
vertical photographs as an aid in faylflg an
unwntmlled mosaic.
float gage—Any of tha tide or stream gages
which prrrif direct reading of changes of water
height by the action of a float, contained within
a restricted pipe or channel, anached fo a
gradua!ed tape or chain.
floatlng llnes-(JCS) In phologrammetry,
lines connecting the same two points 01 detail
on each print of a alereo pair, used to determine
whether or not the points are intervislble. The
Iinas may be drawn directly onto the prints or
superimposed by means of strips o? Iransparenf
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