Surveying in Context

Question 1

What is surveying?

Answer 1

It is concerned with determining the positions of natural and man-made features on or below the Earth’s surface, and with the presentation of this information.

Question 2

What do surveyors do?

Answer 2

They take measurements of real-world objects to make a map or plan either:

1) Analogue e.g. paper
2) Digital (now central to all we do)

Question 3

What is “setting out”?

Answer 3

Establishing location on the Earth’s surface of selected points or lines shown on a map or plan.

Question 4

What is “setting out” often described as?

Answer 4

Surveying in reverse.

Question 5

What does geodetic surveying involve?

Answer 5

It involves large areas: regional, continental, global.

Question 6

What must be done in geodetic surveying?

Answer 6

Horizontal reference surface must take the shape of the earth into account (curvature).

Question 7

What does geodetic surveying require, relating measurements?

Answer 7

High accuracy measurements.

Question 8

When is geodetic surveying used?

Answer 8

In Geodesy and to provide reference positions for other surveys.

Question 9

What does geodetic surveying provide?

Answer 9

A backbone in national mapping (coordinate) systems: OSGB36 which is the reference datum in GB.

Question 10

What is plane surveying?

Answer 10

It is where the coordinate reference surface is a horizontal plane perpendicular to the line of gravity through a point.

Question 11

When is plane surveying valid?

Answer 11

Only for small areas, approximately 10x10km.

Question 12

What is the approximate radius of the Earth?

Answer 12

6300km

Question 13

What is local surveying?

Answer 13

We change the parameters of an ellipsoid (earth) and shift it around in order for it to fit the region of the earth we are interested in.

Question 14

What are surveys classified by?

Answer 14

Purpose

Question 15

What is a topographic survey?

Answer 15

Produces maps of the natural and man-made features. It shows height information.

Question 16

What are engineering surveys?

Answer 16

Provide maps and plans for use in the design of engineering works. may also be concerned with the setting out of new works.

Question 17

What are Cadastral surveys?

Answer 17

Carried out to determine the position of property boundaries for legal purposes. provide the basis of a system for land ownership.

Question 18

What are mining surveys?

Answer 18

They are the determination and recording of positions of underground workings in mines etc. can also be open-pit mines.

Question 19

What are utility surveys?

Answer 19

Determination of positions and management of utilities. Requires specialist techniques e.g. Ground Penetrating Radar.

Question 20

What are Hydrographic surveys?

Answer 20

Surveys of areas offshore generally of the sea-bed for example for oil and gas exploration and production but can also be near shore and in-shore.

Question 21

What is stage 1 of the process for local plane surveys? (3)

Answer 21

PLANNING:

1) Get an overall picture of what is required by visiting the site,
2) decide on surveying techniques
3) instrumentation according to time limits.

Question 22

What is stage 2 of the process for local plane surveys? (2)

Answer 22

MEASUREMENT:

1) determine relative positions and sizes of objects
2) angles and distances.

Question 23

What is stage 3 of the process for local plane surveys?

Answer 23

DATA PROCESSING: usually some data processing of the measurements is needed. Normally carried out by a computer. Method depends on size of area.

Question 24

What is stage 4 of the process for local plane surveys?

Answer 24

DATA PRESENTATION: Various forms of presentation are used to plot and visualise a survey: maps, plans and digital terrain models, etc.

Question 25

What is stage 5 of the process for local plane surveys?

Answer 25

PLOTTING MAPS AND PLANS: Plotted according to certain rules and conventions. Position, shape and size.

Question 26

What is stage 6 of the process for local plane surveys?

Answer 26

PLOTTING SHAPE AND SIZE: On a plan everything is drawn to scale. On a map conventional size and symbols are normally used as not everything can be plotted to scale.

Question 27

What are the basic principles of surveying?

Answer 27

1) Work from the whole to the part 2) Choose a survey method appropriate to the required result. 3) Undertake independent checks at all stages to ensure the accuracy and precision of our work meets the specification. 4) Work systematically and record everything clearly.

Question 28

What does "work from the whole to the part" mean?

Answer 28

Have a control framework that encompasses the whole of our survey and work inwards from that.

Question 29

Name 5 methods in surveying to determine the relative position in plan?

Answer 29

1) Offsetting 2) Tie lines (trilateration) 3) Intersection 4) radiation 5) Resection

Question 30

What is offsetting? (3)

Answer 30

1) Two distance measurements 2) Measure along a distance 3) Perpendicular to baseline AB

Question 31

What is tie lines (trilateration)? (2)

Answer 31

1) Two distance measurements | 2) Measure distance d1 and d2

Question 32

What is intersection? (3)

Answer 32

1) Two angle measurements 2) Measure angles alpha and beta 3) Calculate the distances

Question 33

What is Radiation method? (4)

Answer 33

1) Angle and distance measurements 2) Know coordinates of A and B 3) Measure distances d1 and angle alpha 4) calculate the coordinates of C

Question 34

What is resection? (3)

Answer 34

1) Two angles at unknown points between three known points. 2) Measure angles alpha and beta 3) Calculate the coordinates C

Question 35

What are two surveying techniques to determine relative height differences? (2)

Answer 35

1) levelling | 2) Trigonometric heighting

Question 36

What does levelling consist of? (2)

Answer 36

1) Measure vertical distance between points | 2) Use a level and levelling staff

Question 37

What is trigonometric heighting? (2)

Answer 37

1) Measure vertical angle and slop distance between points. | 2) Calculate the vertical distance in height using trigonometry.

Question 38

How do we measure distances and angles?

Answer 38

Most commonly use total stations and digital levels.

Question 39

What is GNSS?

Answer 39

Global Navigation Satellite Systems

Question 40

What is LiDAR?

Answer 40

It involves measuring the time it takes laser pulses to travel from an aircraft to the ground and back to determine elevation data.

Question 41

What is laser scanning?

Answer 41

Uses a rotating laser distance and angle measuring system to automatically record 3D coordinates of the surface of an object.

Question 42

What are total stations capable of?

Answer 42

Measuring angles and distances with a high degree of precision.

Question 43

What is digital photography?

Answer 43

Uses workstations for mapping in which digital images are displayed on a computer screen.

Question 44

What will an integrated surveying system be made up of? (5)

Answer 44

1) A surveying sensor 2) A data collection hardware and software 3) Computer 4) Data communications 5) Processing and design software

Question 45

Name 2 professional bodies?

Answer 45

1) Royal institution of Chartered Surveyors (RICS) | 2) Royal institution of Civil Engineering Surveyors (ICES)