1. Introduction to basic surveying skills in the Construction & Property Industries
NG1H703
David Harper

2. Basic Surveying Skills
Course tutor – David Harper
Course code – NG1H703
My address is
Room G713
Assessment for the module NG1H703 is via:
- Practical Surveying Exercise (70%)
Open Book Exam – 1 hour (30%)
Homework exercises – they are there for your benefit and will assist your development of the subject. Answers to be ed to me.

3. Introduction to today’s lecture
Maps & plans
Standard units
Angles
Tape Measures

4. Maps and Plans
Since 1791 responsibility for the production of national maps and plans of the UK has been with the Ordnance Survey.
The survey data are plotted on maps, where features are presented in their correct plan location by symbols that themselves are not to scale, at scales of:
1: – all UK on one sheet;
1: – traditional 5 miles to 1 inch motoring map;
1: – traditional 1 inch to 1 mile area map;
1: – traditional 2.5 inches to 1 mile walkers’ map.
In the past the surveys were also presented as a range of larger-scale plans, where buildings, roads and other features were plotted in their correct location and at their correct size, at scales of: (see next slide)

5. Maps and Plans (Cont.)
1: – 6 inches to the mile plan, for site location and the smallest scale of use in engineering works;
1: 2500 – for detail work in rural areas;
1:12500 – for detail work in urban areas
The latter two scales are commonly used for outline design of engineering schemes, utility records and building works.
Since 1970 the Ordnance Survey has been producing digital maps. At first they were just used as a convenient means of reproducing the hard copies of the map in predetermined sheet sizes and a set scales, but recent developments allow a user to specify coordinates of the site location and have the plan plotted in the centre, thus eliminating the need to join sheets for sites located near the edge of traditional sheets.

6. Maps and Plans (Cont.) What is Raster Data?

7. Maps and Plans (Cont.)
Raster data is currently available in colour for the 1: Landranger series of maps and in black and white for 1: scale plans.
In this form, often known as bitmap, the screen image, or printed page, is made up from a series of dots, each being represented by a separate data item in the file. Colours attributed to the dot (in the simplest form black or white) allow adjacent dots to be encoded so that an image is formed.
All of the traditional map scales are also available with the data stored in vector format; here the data file consists of the co-ordinates of points and ends of lines, which can have information describing the feature attached.
Vector files are normally much smaller than the raster equivalent.
The earliest 2D computer graphics were all vector graphics.
Present-day vector graphic files such as engineering drawings are typically printed as bitmaps, after vector-to-raster conversion.

8. Maps and Plans (Cont.)
The Ordnance Survey Superplan service provides plans from vector data for more detailed work. This type of data can be easily resized to any scale and while the standard scales of 1: 1250 in urban areas, 1: 2500 in rural areas and 1: in remote moorland form the database, any other scale can be reproduced.
The map data can also be purchased as computer files, and the resulting plan can be used in geographical information systems, in computer aided design packages and as a base for customer’s command and control systems, e.g. recording the location of underground assets owned by a utility company.

9. Standard Units
DISTANCES = metre = m Note – written to 3 decimal places.
Remember – in the case of a building drawing it may be written in millimetres , however, the drawing will tell you the units of measurement.
1 millimetre = m
1 kilometre = m
Remember – standard unit for setting out especially in engineering is metre. But, building drawings usually under 20 m is millimetres.
AREA = square metre (m²) – applies to buildings
AREA = hectares i.e. 100m x 100m = 10,000 m² – applies to land

10. Standard Units (Cont.) Note – 1 acre = 1 furlong x 1 chain
= 660 feet x 66 feet
VOLUME = cubic metre (m³)
WEIGHT = gram = 1 g
= tonne = 1 t
= kilograms = 1 kg (most popular)
Note – 1 t = 1 m³ of water at 20 degrees Centigrade. Whereas 1 m³ of concrete = 2.4 t

11. Angles Imperial units DMS = Degrees Minutes Seconds = o ‘ “
360 degrees = circle
1 degree = 60’ minutes
1 ‘ minute = 60 “ seconds
Note – 1” second of arc at 200 m = 1 mm.
1 mm
200 m
1 “ second

12. Angles (Cont.) Metric Units 400 gon in a circle.
A gon is a decimal and has 8 decimal places after the decimal point i.e
Metric units are very rarely used, however, the French tend to use them sometimes.
Other Units
1 AU = Astronomical Unit = 93,000,000 miles
9.46 Pm (Petametre) = 1 Light Year = 1 LY
9.46 Pm = m
Parsec = 3.24 LY

13. Tape Measures Steel (not including pocket tapes); and
There are two types of tape measure:
Steel (not including pocket tapes); and
Fibre / Synthetic
All tapes should be manufactured in accordance with BS 4884 ‘Measuring Instruments for Construction Works’.
Steel Tape Measures
10 m to 50 m
They are usually laminated with nylon. If they are not laminated, they will be engraved, they are not allowed to be painted. ICE (Institute for Civil Engineers) state they must be Class II i.e. every mm, cm and m are marked. Do not use Class III tapes because not every mm is marked or count on metres.
Problem with steel tapes are that they are fragile and the steel element can break easily. Do not use tape if it has a kink in it because it is broken.

14. Tape Measures (Cont.)
Steel tapes, however, are accurate +/- 3mm over 30 m. They are also easy to read.
Commonly available lengths are 3, 5, 20, 30 and 100 m. 3 and 30 m tapes are probably the most suitable for general site use.
BS 4884 requires that within the first 300 mm of the tape the tension at which the tape should be used is shown and also the temperature at which the tape was graduated. These two figures are normally 50N (5 Kg) and 20 degrees Celcius.
Cost for 30 m steel tape = approx. £65 + VAT
ICE state that steel tapes can be used for both setting out and surveying.
Note – ICE say you should not use a tape longer than 30 m.

15. Tape Measures (Cont.) Fibre / Synthetic Tape Measures 10 m to 50 m
Glass or cloth fibre
Fibre / Synthetic tapes can stretch
Class II are available
Problem, because fibre tapes stretch therefore they can be inaccurate.
Cost 30 m tape = approx. £40 + VAT
ICE state that fibre tapes can not be used for setting out. It can be used for measuring up (e.g. hole in the road or tarmac on a road) and surveying (e.g. to size up a building).

16. Tape Measures (Cont.)
Sources of error for linear measurement with tapes:
Calibration – New or repaired tapes should be checked against a standard.
Tension and sag – Too much tension causes a tape to stretch. Not enough tension will cause sag if held between tops of pegs.
Temperature variations – Steel tapes are calibrated at a temperature of 20 degrees Celsius , any variation to this temperature will alter the length of the tape.
Reading errors – This can be overcome if you familiarise yourself with the markings of the tape you are using.
The slope of the ground – All dimensions on drawings are given to the horizontal therefore correction should be made for slope.

17. Tape Measures (Cont.) Care of Tapes:
Cleaned and lightly oiled at the end of each working day.
The tape should not be left lying on the ground as small loops will form and when subjected to tension kinks or breakage may occur.
Wherever possible the tape should be kept under tension or wound in.
The extended tape should be carried by two person keeping the tape taut; if this cannot happen then the tape should be dragged from the case end only.
Traffic should not be allowed over the tape.

18. Summary of today’s lecture
Maps & plans
Standard units
Angles
Tape Measures