The 'photogrammetric control' (ground control points) in aerial survey are required for:
Choose the correct answer
Only for taking photographs from aircraft
Absolute orientation and georeferencing — known ground coordinates to convert model to real-world coordinate system
Measuring pilot''s flight path
Calibrating the aircraft compass
Correct Answer
B. Absolute orientation and georeferencing — known ground coordinates to convert model to real-world coordinate system
Why is this the answer?
Ground Control Points (GCPs): surveyed points on the ground with known X, Y, Z coordinates, identifiable on photos. Used for: absolute orientation of stereomodel (scaling, rotating, levelling the model to ground), georeferencing, orthorectification. Minimum 3–4 GCPs per stereomodel (for 6 exterior orientation parameters). With GNSS direct georeferencing: fewer GCPs needed. Accuracy of map = accuracy of GCPs.
Related Surveying MCQs
More solved Surveying questions for AE/JE Civil Engineering exams.
- 'Contour interval' selection for a topographic survey depends on:
- A 'Digital Elevation Model' (DEM) is used in GIS for:
- The 'EDM' (Electronic Distance Measurement) instrument measures distances using:
- The 'levelling staff' reading is corrected for 'curvature and refraction' by the formula:
- The 'photogrammetric stereomodel' from two overlapping aerial photos allows...
- The 'corrections' applied to measured chain/tape lengths include all EXCEPT:
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