Select the CORRECT option(s). Aerial images are prone to external geometric errors due to random movements of the aircraft, which involve changes in ______.
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Think about which exterior orientation elements (position vs angular tilt) change due to aircraft instability, as opposed to ground-related or camera-related parameters.
Step 1: Classify photogrammetric errors by source. Geometric errors in aerial photographs split broadly into errors from the unsteady sensor platform (aircraft) and errors from the shape of the ground. The question restricts itself to the first group.
Step 2: Model the exposure station. At the instant of exposure, a photograph is defined by six exterior-orientation parameters: three positional coordinates ($X_0, Y_0, Z_0$, where $Z_0$ is the flying height/altitude) and three angular coordinates (omega, phi, kappa, defining attitude/tilt). Random aircraft motion perturbs exactly these six parameters between exposures.
Step 3: Link the perturbed parameters to the choices. A change in $Z_0$ is a change in altitude, altering photo scale ($\text{scale} = f / (Z_0 - Z_{avg})$) unevenly if it drifts between exposures. A change in omega/phi/kappa is a change in attitude, tilting the photograph and producing tilt/perspective displacement of image points from their true positions.
Step 4: Why the remaining two choices do not belong. terrain relief is a property of the ground surface, independent of aircraft flight, so it is a ground-related error source. focal length is fixed by the camera and calibrated beforehand, not something that fluctuates because the aircraft is buffeted by wind.
Step 5: Final selection. Random aircraft movement affects exactly the positional height (altitude) and angular orientation (attitude) among the exterior orientation elements. \[ \boxed{\text{altitude and attitude}} \]
