1 - NGA

to the lengths of meridians In order to create Ihe
carves of the lop ard bottom latitudes 01 a
projection.
meridional orthographic mep
prolecllon—A map projection having the
plane of the projection parallel to the plane 01
some selected meridian; the geographic
parallels sutd the cenlral meridan are straight
lines, the outer mertiian is a full circle, and the
other meridians ara a= of ellipaea.
meridional part-The length of the arc of a
meridiin between the Equator and a given
parallel on a Mercator chart, expressed in unitS
of 1‘ of bngltuda at the Equator.
merldlonel plana-Any plane containing the
polar axis of the Eamt. See also astronomic
merldfan plene; geodetic meridian
plane.
mete date basbl. Information about
irrformation, e.Q. a tisf or catalog of directories.
2. Information abouf data, e.g. a directory of
data storage focef ione. See also Data baee
and Deta dictionary.
MIL-HDBK-850
metedata—lmormalion about inforrnat(oh:
more specifically, information about the meaning
of other data.
meteorological chart-Any chart showing
meteorological (weather) information.
meter rod—See precise Ieveflng rod.
metee-and-bounda survey—A method of
dascrlblng the boundaries of tracts of land by
gtifng the bearing and length of each
succesaiva fine. Much of the land in the
nonpublic land States has been eurveyed and
described by fhie method. This melhod is also
used in the surveys of the public lands 10 define
the boundaries of Irregular tracts, such as
claims, grants, and reservations, which are nonconformable
to the rectangular system of
subdivleion.
method of reperltlone—The determination
of Ihe angle between two marks by
accumulating, on fhe horizontal circle of a
repeating theodolile, the sum of a series 01
measurements of tha horizomal angle between
the two mafia.
Matonlc cycf%A period of approximately 19
years, or a computed equivalent, durin9 w~ch
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all phase relationships bafween Moon, Sun. and
Earlh occur, and atter the lapse of which the
phases of fhe Moon refurn 10 a particular date in
the calendar year. Durfng any cycle, new and lull
Moon will recur on approximately the same day
in the calendar year.
metric camera-A specially constructed end
calibrated camera used to obtain geometrically
accurate photographs for use In
photogrammetric hwtruments.
metric mapping euppon date (MMSD)-
Camera model parameters which albw proper
geographic positioning of features scan on
image~ based on sensor position and pointing
angle relative to the aarth’s geoid.
metric photography—The recording of
events by means of photographs, either singly
or sequentially, together with appropriate
coordinates, to form the basis for accurale
measurements,
Metrogon lens—The trade name o! a wideangle
lens for aerial cameras used in mapfring,
charting, and reconnaissance photography. See
also trlmetrogon camera.
mlcrofeafurea—Features of relief, drainage,
and Iandlorms wtilch can be Idanlified on
photographs, but are too small to appear on
maps
micrometer mathod—Tba delerminafion of
the astronomic azimuth of a line by measuring
indirectly with an ocular micrometer attached to
a theodolite or Iransit the horizontal angle
between a selecled slar at its elongation and a
suitable ground mark (light) placed close to the
verlical plane which passes through the star,
and applying that angle to the azimuth of the
star computed tor the epoch o! Ihe observation.
micrometer—An auxiliary device to provide
measurement of very small angles or
dimensions by an insfwment such as a
felescope. See also tilar micrometer; ocular
micrometer: transit micrometer.
mld.1atitude—1. Sea mfddle Iatltude. 2.
(cartography) The one parallel that is a! the
same scale as Indlcaled on a Mercator
project ion.
Middle ldtltude-One-half of the arithmetical
sum of the latitudes of two places on the same
side of the Equetor. Middle Iatltuda is labeled