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3. Parallax Equations
a. Ground Coordinates
The ground coordinate system is similar to that of a single vertical photo. The origin and axes directions are defined by the left photo, Figure E-9, using the actual flight direction.
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Figure E-9 Ground Coordinate System |
Coordinates and elevation of ground points can be determined from parallax measurements using equations E-4 through E-6.
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Equation E-4 |
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Equation E-5 |
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Equation E-6 |
b. Elevations by Parallax
Figure E-10 shows the basic parallax and elevation geometry for two points.
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Figure E-10 Parallax and Elevation Difference |
If we can measure the parallax of both points, we can determine one point's elevation based on the other, Equation E-7.
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Equation E-7 |