Meaning and Types of Survey

Simple Land Survey

Surveying is the science of measurmmg and record distances, angles and heights on the Earth's surface to obtain data fom which accurate plans and maps are made on the Earth’ surface a different positions forthe purpose of producing a plan or map.

object. The distance is measured in a clockwise direction from North distance. Purpose of surveying

• To prepare maps and plans

Types of Simple Land Survey

Explain the pes of simple land survey Surveying can becategorisedinto various types or branches depending on its purpose, fiction and nature. Thetypes or branches include: topographical maps.

shape and size (the Earth's configuration) © Cadastral survey:This kind of survey is conducted with the aim of preparing a legal document such as house plans, town or city boundaries, ete. It is mainly used for ownership purposes.

• Engineering surveys:This kind of survey is conducted for the building and construction

layout of railways, bridges and roads ¢ Geological survey: This kind of survey is condueted with the aim of knowing the distribution of rocks and minerals under the Earth's surface £ ‘Topographical surveying: This kind of survey is carried out forthe purpose of preparing topographical maps. Topographical maps are those maps whose contents include both man-made features such as linear features (roads, railways, telephone lines, water systems, and electricity

poles) and natural features such as rivers, oceans, mountains, ete: The topographical survey has the following ways or methods of conducting the survey: 1.Chainortapesurvey; 2. Theprismatic compasssurvey; 3. Theplane tablesurvey; 4. The technique of levelling

Chain Survey

Chain/Tape Survey

Describe chaintape survey It is @ method of Surveying in which no angles are measured but only linear measurement is taken in the field by using a chain or tape measure.It measures a series of straight lines on the ground with a chain or tape measure and all fixed points relative to theline of iraverseeither by right angles (offieis)orte nes.

Types of Equipment used in Chain/Tape Surveying

Explain different types of equipment used in chainape surveying Chain

• Thechainis made up of steel wire which is divided intolinksandtogs(rings) to facilitate

folding

• Itis sometimes used as 2 unit of measurement
• Ithas brass handles at both ends for easy handling. Thelinkis 0.2m or 200mm in diameter.

+The length is 20m or 30m Tape

• Stee tape
• Linear tape

10mm divisions and numbered at each 100mm (10) divisionsIt is used for measuring short Ranging poles Ranging polesare made up of wood ot light metal and measure about 2m long atthe top, ‘The equipment has stel shades on its legs so it can be stuck into the ground. Ranging poles are painted red and white so that they can be easily seen even from a distance. ‘They are used for making stations.

Arrows Arrowsare made of stl wite of diameter 4mm and their ends are bent into a circle where red cloth is tied to facilitate visibility. They are used for showing points on the ground They are also Pegs Pegsare made of wood 40mm square by 50cm long and are used for permanently marking positions during survey Surveyors' band handle, tis 30m, 50m or 100m long. Is used in projects where more accuracy messurement is required

Cross staff Thecross stuffis made of metal or wood witheye slipsat right angles and is used to measure right angles from the line of traverse Notebook Notebooksare used during field work to record data obtained, The notebook should be of good A hard peneil and a rubber are made. A pencil should be HB or HEB.

Chain/Tape Surveying Activities at School Level

Practice chain/tape surveying activities at school level Methods and procedures involved in chain survey thebooker

• ‘The chains thrown to extend it and disentangle any knots

. The leader takes ten arrows and a ranging rod, and the follower takes a ranging rod

• The follower erects his ranging rodipole atthe firsthase poinnind places a brass handle of

the chain against the ranging rod_ . A leader straighten the chain and inserts an arrow at end of the brass handle. Offsets and tie lines ean now be taken

• ‘The leader drags the chain so that the follower's end ison the leader's arrow; the follower

repested

• Its suitable for small areas of fairly open ground.

2 This used to fill in details on a map whose large features have been surveyed by other methods.

• Its used im mapping small areas of flat or near-flat ground and associated objects, for

‘example paths, roads and railways

• Its used in adding detail to existing plans or large maps.

Advantages of chain surveying

• Its the simplest method of surveying through the old method.
• Its suitable for surveying clear areas,
• It tends not to attract attention
• This suitable for surveying a flat surface on the Parth’s surface, for example a school

compound.

• team be read easity and quickly
• Itcan withstand wear and tear

7 Itcan be easily repaired or rectified in the Feld

Disadvantages of chain survey

1, Itisa slow method of surveying 2, Itis the oldest method of surveying

• It isnot suitable for surveying large areas.
• More difficult areas cannot be chain surveyed.
• Emrors may be encountered due to the use of many chins and other reasons.

6 tis time consuming.

• They are heavy and take too much time to open or fold

8 They become longer or shorter due to continuous use

The Importance of Survey

1, Tehlp to prepare topographical map which shows the hills, valleys, rivers, village, towns, forests, et: of a country properties. 3, help t prepare an enginering map which shows the details of engineering works such 4 Aiep to proparesa itary map showing the road and'ruivay communications wit different parts of country best possible route for toads, railways, ete 6 helps to prepara geological map showing areas including underground resources.

7, 1tbelps to prepare an archaeological map including places ancient relics exis