Traversing 1

Question 1

What is the most common method of providing plan and height control?

Answer 1

Traversing

Question 2

What is Traversing’s main rival?

Answer 2

GPS/GNSS

Question 3

What is traversing?

Answer 3

It’s a means of providing horizontal and vertical control from a combination of angle and distance measurements obtained in a systematic manner.

Question 4

What are the 3 key features of a traverse?

Answer 4

1) Ordered sequence of angle and distance observations
2) Each station must be inter-visible with the adjacent
ones.
3) Must start at a known point and sight to the second known station in order to orientate the traverse.

Question 5

Name 3 types of traverse?

Answer 5

1) Link
2) Loop
3) Open

Question 6

Draw a diagram and describe what is a link traverse.

Answer 6

A link traverse is an example of a closed traverse. It has 3 traverse legs “legs”. A and D are known start and end stations (triangles), P and Q are known reference object stations, B and C are unknown stations.

Question 7

What does a link traverse provide? (2)

Answer 7

1) It provides checks on orientation (bearings) in known stations.
2) Errors in distance, angle and orientation are clearly revealed during computation.

Question 8

Draw a diagram and describe what is a loop traverse.

Answer 8

A loop traverse is another example of a closed traverse, sometimes called a closed polygon. 5 traverse “legs” (n=5). B,C,D and E are the unknown stations.

Question 9

What does a loop traverse provide?

Answer 9

Useful checks on angles observed due to summation of internal and external angles, therefore used extensively on engineering sites.

Question 10

What is the formula for sum of internal angles and external angles in a polygon?

Answer 10

Internal: (n-2)180
External: (n+2)180

Question 11

Draw a diagram and describe what is an open traverse.

Answer 11

Should avoid this type of traverse because the traverse is not closed and open, swinging or flying. there are no checks on final stations or computation.

Question 12

When does open traversing have to be used?

Answer 12

Sometimes has to be used in mining and tunnelling.

Question 13

What do we do with our horizontal and vertical angles obtained from the multiple rounds per station and our measured distances?

Answer 13

Take the mean

Question 14

How do we determine horizontal distances?

Answer 14

Reduce slope distances to the horizontal using the observed vertical angles.

Question 15

What should you prepare in traversing?

Answer 15

An abstract sheet with information needed for computations.

Question 16

What is known as “basic data”?

Answer 16

Data collected in the field.

Question 17

If you have an observed slope distance L what is the horizontal distance and vertical distance?

Answer 17

Horizontal: Lcos(θ)
Vertical: Lsin(θ)

Question 18

What should you do before performing any computations? (2)

Answer 18

1) From pre-processing, abstract a single mean value from rounds per horizontal clockwise angle.
2) From pre-processing, abstract a single mean value per horizontal distance.

Question 19

When traversing what are you required to do at each station? (3)

Answer 19

At each station you require:

1) Clockwise horizontal angle between traverse lines to adjacent stations to determine bearings.
2) Horizontal distances to each of the adjacent stations combined with a bearing to determine the plane rectangular coordinates.
3) If 3D then need instrument that targets heights and vertical angles of new stations.