Map Reading & Basic Techniques ! Read and interpret topographical maps

Understanding our environment Read and interpret physical and human features on topographical maps. Basic techniques of interpreting and evaluating geographical data, which may be represented in various forms, such as graphs, photographs and satellite maps.

Make sure you are familiar with the following components of map-reading Reading Topographical maps 1.Map Symbols (Legend) 2.Grid References 3.Compass Points 4.Scales (Large Scale/ Small Scale) 5. Reading Contour Lines

What do all the lines and symbols mean?

Reading Topographical maps Map Symbols (Legend)

Map Symbols (Legend)

How do I find out where a particular landform is found on the map? How do I specify the location of a physical or human feature?

Northing and Easting Eastings are vertical grid lines that increase from west to east. Northings are horizontal grid lines where their numbers increase from south to north.

Reading Topographical maps Grid References Four Figure Grid Reference: North to South Grid Lines: Eastings East to West Grid Lines: Northings 1521

Six figure grid references

Reading Topographical maps Grid References Six Figure Grid Reference: North to South Grid Lines: Eastings East to West Grid Lines: Northings

How to get to that place I want to go to on the map? Which direction should I go?

Reading Topographical maps Compass Points N North Point

Cardinal Points 12 Intermediate Points North East (NE) North West (NW) South East (SE) South West (SW) North-North-East (NNE) East-North-East (ENE) East-South-East (ESE) South-South-East (SSE) South-South-West (SSW) West-South-West (WSW) West-North-West (WNW) North-North-West (NNW) North (N) South (S) East (E) West (W)

Determining Directions BearingsBearings are compass directions, which are used to obtain the precise directions of one place or feature with another. clockwise direction northThey are measured in degrees in a clockwise direction from the north.

How to Determine Directions using Bearings? straight line joining the two points. 1)To measure the bearing of B from A, draw a straight line joining the two points. line parallel to the Grid North 2)Draw a line parallel to the Grid North through A. 3)Place the centre of the protractor over A, with the 0° on the protractor pointing to the North. 4)Read the bearing off the protractor where the line AB cuts the outer edge of the protractor. A B N 131°

A B N The bearing of B from A is 100° A C Let’s Practice how to read bearings N The bearing of C from A is 180° + 50° = 230°

What happens if I want to drive or take a bus to my destination? How do I find out what is the distance between the two points? So that I can estimate how much time I need to get there?

Measuring distances Scale: ratio of a distance on a map to the actual distance on the Earth’s surface.

Representing a Scale on a map 1) As a statement in words For example, 1 centimetre represents 1 kilometre. This means that 1 centimetre on a map represents 1 kilometre on the Earth’s surface. Therefore, if the distance of a road measured on a map is 9 centimetres, the actual distance of the road is 9 kilometres.

Representing a Scale on a map 2) As a representative fraction (R.F.) This is expressed as a ratio or fraction, for example, 1: or 1/ may mean 1 milimetre represents milimetres or 1 centimetre represents centimetres and so on. Distances can be easily calculated using the R.F. For example, if the distance of a HDB flat from a bus stop is 2 centimetres on a map (1 centimetre represents centimetres), then the actual distance is = 2 X centimetres = centimetres or 0.5 kilometres

Representing a Scale on a map 3) As a line or linear scale A linear scale consists of a line that is divided into units and sub-units such that measurements can be read off easily and accurately. A linear scale can be easily converted into a scale using a statement or a R.F. For example, in the diagram below, a distance of 1 kilometre on the linear scale measures 2 centimetres. This means that 2 centimetres represent 1 kilometres or 1 centimetre represents 0.5 kilometres. Metres kilometres A linear scale

B) Reading Topographical maps 4) Scales (Large Scale/ Small Scale)

4) Scales (Large Scale/ Small Scale)

Measuring distances 1.Ruler 2.Pen 3.String 4.Piece of paper

How the height of the mountain I am climbing? How do I find out how steep is the road I am going on?

Representing heights Spot height –indicates the specific height of a point on a map. –Spot heights are not marked on the ground – they are found only on maps, represented by the a symbol ( ), with its height written next to it. Bench mark –Surveyor’s mark cut in some durable material such as a rock or a building. –It indicates the height of a place above sea level. –A bench mark is represented by a symbol. ( ←)

A trigonometrical point, is a circular metallic disc placed in the ground to show that specific height. It is represented on a ma by a symbol shown by a small triangle or a circle with a black dot inside, represents a concrete pillar called a trigonometrical station. The height of a trigonometrical station is very accurately calculated above mean sea level. This height is printed alongside the trigonometrical point on the map. Trigonometrical stations are usually found on hilltops and mountain peaks Representing heights

Gradient refers to the slope of a feature, such as a road, railway, or river. A gradient may be written as an angle or as an ratio between the vertical rise in a given horizontal distance. Representing heights

Calculating gradient