FUNDAMENTAL SURVEYING Geodesy and Map Projections

Question 1

What shape best approximates the Earth for geodetic purposes?

Accepted Answer

An oblate spheroid (ellipsoid)

Answer

A perfect sphere

Answer

A prolate spheroid

Answer

A geoid exactly

Question 2

What is the geoid?

Accepted Answer

The equipotential surface of Earth's gravity field that approximates mean sea level

Answer

The mathematical ellipsoid used as a datum

Answer

The topographic surface of the Earth

Answer

A type of GPS satellite orbit

Question 3

What is the difference between an orthometric height and an ellipsoid height?

Accepted Answer

Orthometric height is measured above the geoid; ellipsoid height is measured above the reference ellipsoid

Answer

They are identical

Answer

Ellipsoid height is always larger

Answer

Orthometric height uses GPS; ellipsoid height uses leveling

Question 4

What is the current official horizontal datum for the conterminous United States?

Accepted Answer

NAD83

Answer

NAD27

Answer

WGS84

Answer

ITRF2014

Question 5

What is the current official vertical datum in the United States?

Accepted Answer

NAVD88

Answer

NGVD29

Answer

ITRF96

Answer

GRS80

Question 6

A 'conformal' map projection preserves which property?

Accepted Answer

Shape (angles) locally

Answer

Area

Answer

Distance everywhere

Answer

Direction from the center only