CUBERectangular solid figure in which all six
faces are square.
CUTTING PLANE LINESThick, heavy lines
used to indicate a plane or planes in which a
sectional view is taken.
CYLINDERA solid figure with two equal
DATUMAny numerical or geometrical quantity
that serves as a reference or base for other
quantities. It is described by such names as
geodetic, leveling, North American, or tidal
datum, depending upon its purpose when
DATUM LINESDark medium lines consisting
of one long and two short dashes evenly spaced;
used to define a line or plane of reference.
DECIMALThe result of dividing the numerator
(top number) of a fraction by the denominator
(bottom number); for example, 1/2 = .5,
3/8 = .375, 17/100 = .17.
DECLINATIONThe angle between true north
and either grid or magnetic north.
DEFLECTION ANGLEA horizontal angle
measured from the prolongation of the preceding
line, clockwise or counterclockwise as necessary,
to the following line.
DEGREEA 360th part of the circumference of
a circle; also, a 360th part of a revolution about
a point; used to define the size of an angle.
DEPARTUREIn a plane survey, the amount
that one end of a line is east or west of the other
end. The plane coordinates of a point are known
as the casting and northing of the point, and the
departure is the difference between the castings
of the two ends of the line, which may be either
plus or minus.
DESIGN MANUALS (DMs)Publications con-
taining guidelines set forth by the Naval Facilities
DETAIL PAPERHeavy opaque, buff, or
neutral green drawing paper that takes pencil well.
DIAGONALA line that connects any two
nonadjacent corners of a plane figure.
DIAMETERA straight line passing through the
center of a circle or sphere whose ends terminate
at the circumference or surface.
DIMENSION LINEA thin, unbroken line
(except in the case of structural drafting) with each
end terminating with an arrowhead; used to define
the dimensions of an object. Dimensions are
placed above the line except in structural drafting
where the line is broken and the dimension placed
in the break.
DIRECT LEVELINGThe determination of
differences of elevation by means of a continuous
series of short horizontal lines. Vertical distances
from these lines to adjacent ground marks are
determined by direct observations on graduated
rods with a leveling instrument equipped with a
DIRECT READINGThe reading of the
horizontal or vertical circle of a theodolite or
engineer transit with the telescope direct.
DISCREPANCY1. The difference between
duplicate or comparable measures of a quantity.
2. The difference between computed values of a
quantity obtained by different processes in the
DISPLAY CHARTChart used to convey data
to nontechnical audiences.
DIVIDERSInstrument used to transfer
DRAFTING MEDIAMaterials used to draw
on. Basically, three types are used: paper, cloth,
EASTINGOne of the two values indicating the
position of a point on a grid system. The casting
coordinate is abbreviated E.
ELEVATIONThe vertical distance of a point
above or below a reference surface, or level
datum; often abbreviated ELEV.
ELLIPSEA plane closed curve having the sum
of the distances from any point on the curve to
two fixed points a constant.
ENGINEERS SCALEA scale used whenever
dimensions are in feet and decimal parts of a foot,
or when the scale ratio is a multiple of 10.