Question

The phenomenon 'crab and drift' is associated with which method of survey

• A. \( \text{Triangulation} \)
• B. \( \text{Astronomical survey} \)
• C. \( \text{Aerial photogrammetry} \)
• D. \( \text{Tacheometric survey} \)

Hint:

Think of 'crab' as the airplane flying slightly sideways and 'drift' as being pushed off course by the wind during aerial surveys.

Answer 1

The Correct Option is C

The phenomena of 'crab' and 'drift' are associated with aerial photogrammetry. \begin{itemize} \item Crab refers to the condition where the aircraft's longitudinal axis is not aligned with the direction of flight, causing the images to be rotated relative to the flight line. \item Drift is the lateral deviation of the aircraft from the planned flight line due to wind. \end{itemize}