Topic 6 Azimuths And Bearings; Angle Measurement

Question 0

Meridians

Answer 0

The direction of a line is described by the horizontal angle that it makes with a reference line or direction.
3 meridians: geographic, magnetic, assumed.

Question 1

Basic Requirements for angle measurement

Answer 1

Reference or starting line
Direction of turning
Angular distance (magnitude)

Question 2

Geographic Meridian

Answer 2

Based on the direction of gravity and the axis of rotation of the earth.

Question 3

Magnetic Meridians

Answer 3

Directions taken by the magnetized needle of a compass.

Question 4

Assumed Meridian

Answer 4

An arbitrary direction taken for convenience (good for limited extent survey), can’t be re-established.

Question 5

Azimuth

Answer 5

Angles measured clockwise from a given reference direction, usually, North.
Military and Astronomers use South
Every line has two directions; forward, backwards.

Question 6

Bearings

Answer 6

Always < 90
Expressed with quadrants: NE, SE, NW, NE
Back bearing: ONLY reverse the direction of the letters, angle is the same.

Question 7

Instruments Used for Angle Mearsurements

Answer 7

Theodolite

Total station

Question 8

Traverse

Answer 8

Defined as a series of successive straight lines (courses) that are connected together.
May be closed as the boundary lines of a piece of land or open as for a highway.

Question 9

Several angles used in Traversing

Answer 9

Interior Angles
Exterior Angles
Deflection Angles

Question 10

Interior Angles

Answer 10

Enclosed by the courses of a closed traverse.

Question 11

Exterior Angle

Answer 11

Not enclosed by the courses of a closed traverse.

Question 12

Deflection Angle

Answer 12

Angle between the extension of the preceding line and the present one.
R -> deflecting right
L -> deflecting left