Certified Photogrammetrist Cheat Sheet 2026

The 30 highest-yield Certified Photogrammetrist facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. In bundle adjustment, what is minimized during the least-squares solution? → The sum of squared residuals of image coordinate measurements
2. What does the term 'block of photographs' refer to in aerial triangulation? → A collection of overlapping photographs covering an entire project area
3. Which UTM zone covers New York City? → Zone 18N
4. What is the principal point in camera calibration? → The point where the optical axis intersects the image plane
5. Which type of ground control point provides both horizontal position and elevation? → Full control (3D)
6. What is the term for the smallest object that can be detected by a sensor? → Spatial resolution
7. What role does the 'datum' play in aerial triangulation? → It defines the coordinate system to which the solution is referenced
8. What is a map projection? → A method for flattening Earth’s surface to a map
9. Which type of aerial camera lens has an angular field of view greater than 100 degrees and is used for small-scale mapping? → Superwide-angle lens (about 120°)
10. What is the minimum number of ground control points needed to define a 3D datum (remove all datum defects) in a photogrammetric block? → 3 full 3D control points (not collinear)
11. What is 'occlusion' in the context of dense image matching? → Areas not visible in one or more images due to blocking by objects
12. What is the overlap percentage typically required between consecutive aerial photos? → 60%
13. What is 'parallax bar measurement' used for in analogue stereo photogrammetry? → Measuring x-parallax differences between points to compute relative elevations
14. What causes decentering (tangential) lens distortion? → Misalignment of optical elements from the optical axis within the lens system
15. In UAV/drone photogrammetry, what overlap configuration is typically recommended for high-quality 3D reconstruction? → 80–90% forward overlap and 70–80% sidelap
16. Which atmospheric condition negatively impacts aerial photogrammetry quality? → Heavy cloud cover
17. What is the role of a flight plan in aerial photogrammetry? → To define image coverage paths and overlaps
18. Why is multi-spectral imaging valuable in remote sensing? → It captures images in multiple wavelength bands
19. The image scale (s) of a vertical aerial photograph with focal length f taken at flying height H above datum is expressed as: → s = f / H
20. What algorithm is most commonly used for automatic image matching to generate dense point clouds? → Semi-Global Matching (SGM) or Multi-View Stereo (MVS)
21. What is the significance of sidelap in aerial data acquisition? → Ensures overlap between flight lines
22. What is 'noise filtering' in point cloud processing? → Eliminating outlier points that do not represent actual surfaces (e.g., flying points)
23. What is the collinearity condition in photogrammetry? → The object point, perspective center, and image point all lie on a straight line
24. What is remote sensing primarily used for in photogrammetry? → Capturing spatial information from a distance
25. What type of distortion is unavoidable when projecting Earth’s curved surface onto a flat map? → All of the above
26. Which factor determines how frequently a satellite can revisit the same location? → Temporal resolution
27. The f-number (f/stop) of a photogrammetric camera lens is defined as: → The focal length divided by the effective aperture (entrance pupil) diameter
28. What is 'map generalization' in the context of photogrammetric mapping? → The process of simplifying and selecting map features appropriate for the target map scale
29. What is the primary purpose of land surveying? → Measuring and mapping land positions and boundaries
30. Which color band is most effective for detecting healthy vegetation? → Near-infrared band