Certified Photogrammetrist Surveying Principles & Spatial Analysis

Question 1

A GNSS receiver reports an ellipsoid height (h) of 152.40 m at a point where the geoid height (N) is -30.10 m. What is the orthometric height (H)?

Accepted Answer

182.50 m

Answer

Orthometric height is H = h - N, so 152.40 - (-30.10) = 182.50 m.

Question 2

Which reference ellipsoid is used by the North American Datum of 1983 (NAD83)?

Accepted Answer

GRS 80

Answer

NAD83 is defined on the GRS 80 ellipsoid, which differs only negligibly from WGS 84.

Question 3

What is the scale factor along the central meridian of a Universal Transverse Mercator (UTM) zone?

Accepted Answer

0.9996

Answer

UTM uses a central meridian scale factor of 0.9996 to balance distortion across the 6-degree zone.

Question 4

To convert a horizontal ground distance to a State Plane grid distance, the ground distance is multiplied by which factor?

Accepted Answer

The combined factor (grid scale factor times elevation factor)

Answer

The combined factor accounts for both reduction to the ellipsoid and projection scale distortion.

Question 5

In the State Plane Coordinate System, which projection is typically used for states with a predominantly east-west extent such as Tennessee?

Accepted Answer

Lambert Conformal Conic

Answer

Lambert Conformal Conic minimizes distortion along east-west bands between its standard parallels.

Certified Photogrammetrist Practice Test