1 - NGA

MIL-HDBK-850
Bacfro-Wurdom hams-llne ftIsifMrlng
apparatfsa-A compensating bsse fine
rnaasurrng apparatus having a measuring
element corrymsed of a bar 01 hon and a bar of
brass, each a fiila lass than 6 maters in length,
hefd together firmly at one end, with tha free
ends so connected by a mrnpansating lever as
10 lorrn a cxmrpansatlng apparatus.
beck aslmuth-1. (geodetic surveying) If the
azimuth of point B frem point A is given on a
reference sphere or elllpeolcf, the back azimuth
Is the azimuth of point A from point B. Because
of the cmwergaxe of !he rnarfdans, the
forward and backward azimuths 01 a line do not
differ by exactly 180”, except where A and B
have the same geodetic bngitude or where the
gaodefii tetitudes o! bolh pdnts are 0“. 2.
(plane surveying) When referred to a plane
rectangular coordinate system, same as above
except forward and backward azimuths differ by
exactly 180”. See also azimuth, definffion 1.
back bearing-l. A beering differing by 180”,
or measurad in the oppxffe direction from a
gh+en bearing. Also calied reciprocal
bearing. 2. The bearing al the opposite end
of a line from the observer as measured lrom
the true meridian al the opposite end of the line,
The back bearing on all lines (other Ihan norfheoufh
~M3S) are diierenf from the bearing at the
obaerve~s sta!lon. They differ by the amount of
cerwergancy of the meridians between the two
peinte.
back local distance-Se e beck local
Iongth,
back focal length-The distance measured
along the lens axis from the rear vertex 01 the
Iena to the plane of best average definition, Also
calied back focal dlatanca; back tocua.
back tocua-see beck focal length.
backalght—1. A sight on a previously
established survey point or line. 2. (traverse) A
sight on a previously estsbtiehed aunray point,
which is not the closing sight of the traverse. 3.
(leveling) A reading on a rod held on a poim
whose elevation has been previously
detemrinad and which is not fhe cbsing sighf of
a ievel circatit: any such rcd reading used to
B
determine he’~ht of Insfnsrrranf prior to making
a forealgM. Also cetlad plus slgfst.
backatep-The method of determining the
offsata for the bottom krthude of a pro@fbn by
measuring the appropriate distances tiwrr from
the top fatiiude of a chart
backup-An image pdmad on the reversa side
of a map eheaf already printed on one stie.
Also the printing of such Images.
bafanclng a 8urvey-Distributing corrections
through any traverse to eliminate the enor of
closure, and to obtain an adjusfed poslfion for
each traveree station, Also called traverse
adjustment. Sea also Compaaa rula;
dlstence prorate rote; transit rule.
Baldwin solar charl-A chart designed for
orienting a plantable by means 01 fhe Sun%
ehadow.
balllstlc camara—A precision terrestrial
camera, usuatty employing glass plates, used al
nigfw to photograph such objects as rockets,
missiles, or satellites against a star background.
Also caliad tracking camera. See also BC-4
camera.
band Interleaved by llne-A spaciflc
implementation of a nrulfivariate raster detaeat.
For each line in the raster, the values of each of
the variables or bands are stored in sequenca,
bafore the set for the succeadng fine.
band sequen!iaf—A specific implementation
of a rnuffivariate raster data act. The complete
data array for each separate variable or band is
stored indapandenfty of the other variables.
band—A channel. A range of wavelengths of
elactromsgnat!a radiation.
bar check—A mathod of field calibrating the
sounding equipment used in hydrographic
survey by euspanding a bar or disc beneath the
transducer at various depths,
bar scale-See graphic 6cale.
Bsrlow ievellng rod-A speaking rod ma~ed
with triangles each 0.02 foot in heighf.
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