1 - NGA

I
I
1
MIL-HDBK-850
on a parallel of latitude fmm an inWlal point, and
from wfrich are Initfeted other fh’res for the
cadwrral euwey of the Pubfii fend6 within the
araa covered by lhe print’pal me@lan that runs
lhrough the same intttsl point. S. (navigation)
Tfre Iina between two radio trWt6t’fIltfiIVJ 6tati0n6
operating in Cc@mcfbn for the detemdnsfbn of
a line 01 posltiin, as the two sfaibne of a loran
system.
bsee mrsnuacrlpl+ee compilation
manuscript.
bees map-(JCS) A map or charl showing
certain fundamental information, used as a
base umn which eddifiinal data of eoecialized
i~im- i~ con@ed or werprimed. Aiso, a r+ap
containing all the information fmm which maps
Showiw specialized information can be
prepared. Saa also chart base; map.
base net—A small net of trianglas and
quadrilaterals, efati!ng from a meaeured baae
fine. and connec4iW with a line of the main
scheme of a triangulation net.
baas sheet—A sheel 01 dimensionally stable
material upen which the map projection and
ground control are ploftti, ati upon which
stereohiangulation or steremmmpilation is
performed.
base atetlon—1. (surveying) The Pint from
which a survey begins. 2. (gravlfy) A gaogrephic
position whose ebeolute gravhy valua is known.
In expiration. a reference station where
quantities under investigations have known
valuea or may be under rapealad or continuous
measurement in order to establish additional
etalions in relatlon to ft.
beee tape-A tepe or band ot metal or alloy,
so designed and graduated ati of euch
excellent workmanship lhal it is sui!abla tor
msasurlng lengths of lines (base lines) for
mntrollhrg triangulation, and for measuring the
lengths of first- and sscoti-order travarae fines.
baw tltt-Tha Incllnat!on of the ak base with
raspecf to the horizontal. See also baaal
orlsntatlon.
baw.allftude ratio-l%e ratio between the
air basa length and the flight atfflude 0! a
stereoscopic pair of photographs. This ratio is
reterred to as the K-factor. More commonly
called baae.height ratio. Also indicated
functionally as B/H.
28
basa-height ratio—See brsao-altltude
ratio.
baae.llne eatenalon-(navigation) Tha
cati]nuat”mn ot the base tine in both directions
beyorut the tmnsmhfem of a pair 01 rad~
stations o~rating in oonjtmcfion for
datamtinetion of a line of po6ition.
base-llne lavele-A laval Ilne nsn abng a
base line to determine and establish the
elevathn of the base-line stations.
ba$e4ine terminal ●tatlone-The
monumented atatiorre rnatldng the and POims of
a baea line.
basement contoure-Conlours on lhe
surtace of Ihe basemem complex or basic
me!arrwrphic and volcanic rocks underlying an
area.
baelc controf-Horizontal and varflcal control
Of third- or highermrder accuracy, datemnined in
the field and permanently markad or
monumerrted, that is required to control turther
surveys.
basic cover-(JCS) Coverage of any
Installation or area of a permanent nature with
which later twerege can be compared to
discover any changes fhat have Iakan placa.
See also comparative cover.
bathygrephlc—Descnptive of ocean depths.
Bethymatrlc ArChlVe Data (BAD)-in the
DMA Digital Production System, tha Battsymetrii
Archive Data (BAD) layer includes afI soundings
trom all the wrveya taken. Tha eoundiig data
in the BAD layer will evemualiy be extremely
dense. Also Included is accaracy and source
dsta, such as the time the Survey was taken,
whera if was taken, and how It waa tSkWr.
Bathymewlc Modal Data (BMD)-in the
DMA Digital Production Systam, soundings trom
the Bathymalric Archive Data layer are safecfed
to form the Bathymetric Model Data (BMD) layer.
The soundings in the BMD layer are the most
critical of all the eoundings taken. Thesa
soundings form the medel of the esean floor for
the oompifation of Nautical Charts. See also
Balhymetrlc Archive Data.
Bathymetric Nwlgatlon Charte (BNC)-