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. A sensor with 12-bit radiometric resolution can record how many distinct brightness levels? → 4,096
2. To convert a horizontal ground distance to a State Plane grid distance, the ground distance is multiplied by which factor? → The combined factor (grid scale factor times elevation factor)
3. In bundle adjustment, what is minimized during the least-squares solution? → The sum of squared residuals of image coordinate measurements
4. What does the term 'block of photographs' refer to in aerial triangulation? → A collection of overlapping photographs covering an entire project area
5. Which UTM zone covers New York City? → Zone 18N
6. Across most of the conterminous United States, what is true of the geoid height N relative to the GRS 80 ellipsoid? → It is negative, so the geoid lies below the ellipsoid
7. What is the principal point in camera calibration? → The point where the optical axis intersects the image plane
8. The strong near-infrared reflectance of healthy green leaves is primarily caused by what? → Internal scattering by the spongy mesophyll cell structure
9. In a conformal projection grid, what does the convergence angle describe? → The angle between grid north and geodetic (true) north
10. Boresight calibration in an integrated GNSS/IMU camera system determines what? → The small rotational misalignment between the IMU body frame and the camera frame
11. Which type of ground control point provides both horizontal position and elevation? → Full control (3D)
12. Which reference ellipsoid is used by the North American Datum of 1983 (NAD83)? → GRS 80
13. Which projection keeps areas true, so it is preferred for thematic land-cover maps of the conterminous United States? → Albers Equal-Area Conic
14. What is the term for the smallest object that can be detected by a sensor? → Spatial resolution
15. What role does the 'datum' play in aerial triangulation? → It defines the coordinate system to which the solution is referenced
16. Rayleigh scattering, which causes haze in aerial imagery, affects which wavelengths most strongly? → Blue
17. What is the spatial resolution of the panchromatic band on the Landsat 8/9 OLI sensor? → 15 m
18. Geodetic latitude is defined as the angle between the equatorial plane and which line? → The ellipsoid normal at the point
19. What is a map projection? → A method for flattening Earth’s surface to a map
20. 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°)
21. 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)
22. What is 'occlusion' in the context of dense image matching? → Areas not visible in one or more images due to blocking by objects
23. Identifying a building as a high school because it is adjacent to a running track and football field uses which interpretation element? → Association
24. What is the overlap percentage typically required between consecutive aerial photos? → 60%
25. Which spectral band is most useful for distinguishing healthy vegetation in multispectral acquisition? → Near-infrared
26. Which projection is typically used for State Plane zones that extend mainly east-west? → Lambert Conformal Conic
27. What is 'parallax bar measurement' used for in analogue stereo photogrammetry? → Measuring x-parallax differences between points to compute relative elevations
28. What causes decentering (tangential) lens distortion? → Misalignment of optical elements from the optical axis within the lens system
29. In UAV/drone photogrammetry, what overlap configuration is typically recommended for high-quality 3D reconstruction? → 80–90% forward overlap and 70–80% sidelap
30. Which radar band offers the greatest penetration into forest canopy among these options? → L-band