Parameters that are dimensionless and are expressed to nearest 10
units:
RF Representative Fraction
PS Photo Scale
PSR Photo Scale Reciprocal
MS Map Scale
MSR Map Scale Reciprocal
Parameters that are expressed to nearest meter:
GD Ground Distance
Dat Datum Plane; the use of the notation Dat (instead of DP) is to
ovoid confusion between this parameter and the abbreviation (DP) used for
Difference Parallax found in subsequent chapters
H Altitude of aircraft above MSL
H-h Altitude of aircraft above a specific reference datum (e.g., datum
plane or average elevation, or point elevation)
Parameters that are expressed to nearest 0.1 meter:
hD Elevation of Data above MSL
hav Average ground elevation above MSL
hp Elevation of a ground point P above MSL
ho Height of an object or difference in height of two points
Parameters that are expressed to nearest 0.1 millimeter:
MD Map Distance
PD Photo Distance
f Camera focal length
x Photographic x-coordinate measured with respect to the axes defined
by the fiducial marks of the tilted photograph
y Photographic y-coordinate measured with respect to the axes defined
by the fiducial marks of the tilted photograph
x' Photographic x-coordinate after tilt correction
y' Photographic x-coordinate after tilt correction
Parameters expressed in degrees:
a Depression angle of an oblique photograph
from the true horizon
b Rotation angle (180o - swing
angle) of a tilted photograph
s Swing angle
q Angle of tilt on a vertical photograph
Other abbreviations:
A Area
PA Polygon Area
TA Total Area
DCP Dot Counted in a Polygon (or aggregates of polygons
of the same category)
DT Total of Dots counted in the total area
CF Correction Factor
AE Area Equivalent per dot
Dcm Number of dots per square centimeter
DI Number of dots per square inch
sin sine
cos cosine
tan tangent
cot cotangent
m meter
cm centimeter
mm millimeter
in inch
ft foot/feet