a, b, c, etc. 
B 
B 
Bx, By, Bz 
b 
bz, by, b, 
M 
m 
my, Mya, CLC. 
N 
vus os 
x 
"DN 
, B, C, etc. 
DEFINITIONS OF TERMS AND SYMBOLS 1159 
24.2 Phologrammetric Symbols 
24.2.4 LETTER SYMBOLS 
Matrix of the coefficients of residuals in a least-squares solution. 
The coefficient of a residual (i.e., an element of A). 
Semimajor axis of the earth ellipsoid. 
Sometimes used instead of numbers to identify successive ground points or 
camera stations. 
Sometimes used instead of numbers to identify image points corresponding 
to the ground points 4, B, C, etc. 
Matrix of the coefficients of parameters in a least-squares solution. 
Base length (i.e., the physical distance between camera stations). 
Components of the base length in an exterior coordinate system. 
Base length-at the scale of the stereomodel; coefficient of a parameter (i.e., 
an element of, B); semiminor axis of the earth ellipsoid. 
Components of the base length at the scale of the stereomodel. 
Grid convergence. 
As a superscript or subscript, used to identify the coordinates of a camera 
station (e.g., X*, Y*, Z*, or the letters L or -O also may sometimes be 
used); alternative for focal length (f). 
Displacement of a photographic image due to any cause. 
Difference in height or elevation (difference in parallax); d is used here to 
imply difference, not differential. 
Easting in grid coordinates. 
Eccentricity of the earth ellipsoid. 
Focal length of a camera; flattening of the earth ellipsoid. 
Height or elevation of camera stations above sea level datum (unless 
specified otherwise). 
Height or elevation of a ground station or object above sea level datum 
(unless specified otherwise). 
A unit or identity matrix. 
Apparent ground position of the isocenter. 
Isocenter on a photograph (see fig. 24-1); as a subscript, identifies the co- 
ordinates of the ith camera station (e.g., X,^, Y,^, Zi. 
As a subscript, identifies the coordinates of the jth ground point (e.g., X,, 
y, Z;). 
Lens point or camera station; may be used as a superscript or subscript to 
identify the coordinates of a camera station (e.g., Xz, Vi, Z.). 
A 3-by-3 orthogonal matrix of direction cosines, usually specifying the 
orientation between the photograph coordinate system and an exterior 
coordinate system. 
Magnification; a factor which denotes the ratio of a dimension on a photo- 
graphic copy to the corresponding dimension on the negative. 
Alternative for standard error or standard deviation. (See also 9.) 
Elements of M. 
A matrix of the coefficients of a set of normal equations. 
Ground nadir point; northing in grid coordinates; radius of curvature for 
the prime vertical of the earth. 
Nadir point on a photograph. 
Origin point of perspective, lens point, camera station; origin of a system of 
space coordinates relative to a photograph. : 
Sometimes used to designate a photograph principal point. (See also p.) 
Alternative for weight matrix (inverse of covariance matrix). 
Ground principal point. 
Photograph principal point. 
x parallax corresponding to elevation difference. 
y parallax, lack of correspondence. 
Radial distance from any specified photograph center to an image.