CENTER FOR PHOTOGRAMMETRIC TRAINING
FERRIS STATE UNIVERSITY
SURE 340 - Photogrammetry Spring 2008/09
Lab #6
PURPOSE: The purpose of this lab is to have the students make a series of parallax
measurements on a set of photographs to determine the air base (B),
flight altitude (H) and the elevations of a series of points using the
parallax equations.
GIVEN: f = 152.99mm
B = 600 m (initial assumption)
Elevation of the football field = 297.9m
PROCEDURE: 1. Orient the two photographs (8486-2-7 and 8486-2-8) using the
stereoscope and establish the flight line axis system. Mark the
flight line axis system on the photos and the corresponding y-
axis perpendicular to the flight line.
2. Measure the photo coordinates of the football field (100 yards)
and compute the ground coordinates using the parallax formulas
X = B
p x ; Y = B
p y
⎛
⎝
⎜⎞
⎠
⎟⎛
⎝
⎜⎞
⎠
⎟
Compute the distance between the two points using the
Pythagorean theorem. This distance should be 300'. If the
computed distance is within 1' of being 300', the air base is that
initial approximate value. Otherwise, compute a new air base
using the relationship
new
initial
true
computed
B
B = AB
AB
With the new value for the air base, compute the ground
coordinates and distance again. This process is repeated until
the computed and true distances of the field agree to within 1' of
each other.
3. Note that the air base can be computed using the formula
