To define a reference surface for measuring positions on the Earth

To determine the Earth's shape and size

To establish a coordinate system for mapping

All of the above

A geodetic datum is a set of parameters that define the Earth's shape and size, while a coordinate system is a method of representing locations on the Earth's surface.

A geodetic datum is a global reference system, while a coordinate system is a local reference system.

A geodetic datum is used for measuring positions on the Earth's surface, while a coordinate system is used for representing locations on maps.

All of the above

Horizontal datums, vertical datums, and geocentric datums

Horizontal datums, vertical datums, and local datums

Horizontal datums, vertical datums, and global datums

Horizontal datums, vertical datums, and regional datums

World Geodetic System 1984 (WGS84)

North American Datum of 1983 (NAD83)

European Terrestrial Reference System 1989 (ETRS89)

International Terrestrial Reference Frame 2014 (ITRF2014)

A geoid is a mathematical model of the Earth's shape, while an ellipsoid is a physical model of the Earth's shape.

A geoid is a global model of the Earth's shape, while an ellipsoid is a local model of the Earth's shape.

A geoid is used for measuring elevations, while an ellipsoid is used for measuring positions.

All of the above

A geodetic datum defines the origin and orientation of a coordinate system.

A coordinate system defines the units of measurement used in a geodetic datum.

A geodetic datum is used to transform coordinates from one coordinate system to another.

All of the above

A reference ellipsoid, a geoid, and a coordinate system

A reference ellipsoid, a geoid, and a projection

A reference ellipsoid, a geoid, and a transformation

A reference ellipsoid, a geoid, and a datum shift

A horizontal datum defines the origin and orientation of a coordinate system in the horizontal plane, while a vertical datum defines the origin and orientation of a coordinate system in the vertical plane.

A horizontal datum is used for measuring positions on the Earth's surface, while a vertical datum is used for measuring elevations.

A horizontal datum is global, while a vertical datum is local.

All of the above

A geocentric datum is a datum that is centered on the Earth's center of mass, while a geodetic datum is a datum that is centered on the Earth's surface.

A geocentric datum is a global datum, while a geodetic datum is a local datum.

A geocentric datum is used for measuring positions in space, while a geodetic datum is used for measuring positions on the Earth's surface.

All of the above

A datum shift is a change in the origin and orientation of a coordinate system, while a coordinate transformation is a change in the units of measurement used in a coordinate system.

A datum shift is a global change, while a coordinate transformation is a local change.

A datum shift is used to transform coordinates from one datum to another, while a coordinate transformation is used to transform coordinates from one coordinate system to another.

All of the above

North American Vertical Datum of 1988 (NAVD88)

National Geodetic Vertical Datum of 1929 (NGVD29)

International Great Lakes Datum of 1985 (IGLD85)

Puerto Rico Vertical Datum of 2002 (PRVD02)

A geodetic height is the distance between a point and the reference ellipsoid, while an orthometric height is the distance between a point and the geoid.

A geodetic height is a global measurement, while an orthometric height is a local measurement.

A geodetic height is used for surveying and mapping, while an orthometric height is used for navigation.

All of the above

Mean sea level is the average height of the sea's surface over a long period of time, while a geoid is a mathematical model of the Earth's shape.

Mean sea level is a global measurement, while a geoid is a local measurement.

Mean sea level is used for navigation, while a geoid is used for surveying and mapping.

All of the above

A geoid undulation is the difference between the geoid and the reference ellipsoid, while a vertical deflection is the angle between the geoid and the reference ellipsoid.

A geoid undulation is a global measurement, while a vertical deflection is a local measurement.

A geoid undulation is used for surveying and mapping, while a vertical deflection is used for navigation.

All of the above