interpreting topographical maps

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CHAPTER 5

INTERPRETING

TOPOGRAPHICAL MAPS


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Learning Outcomes

You will learn:

to interpret physical and human

environments shown on

topographical maps


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Lead-in: Road Map to Treasure! (Answers)

1. The compass on the bottom right hand corner of the

map and the series of straight lines indicate thecompass directions. The map symbols represent thephysical features found on the island such as the trees,rivers and mountains. The red marks on the map couldbe the location of the treasure.

2. The map helps me to locate my position in relation tothe position of the treasure on the island.

3. I would have to constantly check my position using acompass to ensure that I am traveling in the correct

direction. I would also observe the environmentclosely and compare it to the symbols on the map toensure that I am moving towards the location of thetreasure.


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Topographical Maps

Topographical maps show the details of the

physical and human features in an area. They are used to locate specific places as

well as to understand the physical and

human environments

of these places.

What physical

and human

features canyou see in the

map?


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Using Grid References to Describe Locations

Grid lines are the vertical and horizontal lines

which form a grid dividing a map into grid squares

Vertical grid lines are called eastings because

their numbers increase eastward

Horizontal grid lines are called northings becausetheir numbers increase northward

A grid reference occurs at the point when an

easting crosses a northing Grid references are used to describe the location

of any area or feature on a map


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Using Grid References to Describe Locations:Four-Figure Grid References

A four-figure grid reference can be used to

locate the grid square of an area or a largefeature on a map.


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Using Grid References to Describe Locations:Six-Figure Grid References

A six-figure grid reference can be used to

find the exact location of a feature on amap


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Finding Directions on a Map: Compass Points

A compass helps us to find the direction of a

place from another.

Fourcompass points are marked on most

compasses: north, south, east and west.

Compass points are shown by the north arrowon maps.


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Finding Directions on a Map: Compass Bearings

Compass bearings are directions measured

in degrees and are more exact than compasspoints.

They are measured from north in a

clockwise direction.

North: 0o

East: 90o

South: 180o

West: 270o


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Finding Directions on a Map: Compass Bearings

Finding thedirection of a

location usingcompassbearings


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Measuring Distances on a Map

Measuring straight-line distance:

Use a ruler to measure the length between

two points on the map.

Use the scale of the map to find the actual

distance on the ground.

If the scale of the map is 1: 10 000, then alength of 1 centimetre on the map means that

the distance between two points is 10 000

centimetres on the ground.

Another way to measure straight-line distance

between two points is to mark out the distance

on a piece of paper and measure it against the

scale.


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Measuring Distances on a Map

Measuring curved distance:

Place one end of a string at the startingpoint and hold it down firmly.

Use the string to trace the path.

When the ending point is reached, makea mark on the string.

Remove the string, straighten and

measure it against the scale or a ruler.

Use the scale to convert the length to the

actual distance on the ground.


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Measuring Distances on a MapMeasuring curved distance: Another way to

measure the curved distance between two points is

to use the straight edge of a piece of paper.


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Interpreting the Physical Environment shownon a Topographical Map

The physical environment consists of physical

features such as plants and hills

Relief refers to the physical shape and slope of

the Earths surface

One common way of showing relief of aparticular area on a

topographic map is

through the use of

contour lines.


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Using Contoursto Represent Relief

A contour is an imaginary line joining places of thesame height above sea level.

Contours tell us about the shape and slope of the land.

Contour lines that are close together represent steepslopes.

Contour lines that are far apart represent gentle slopes.

When there are no contour lines or the contours are veryfar apart in an area, it means that the land is almost flat.


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Contour Patterns and Physical FeaturesHills and mountains

Contours joined in a circular fashion with the contour linesincreasing in height towards the centre

A hill is gently sloping andless than 600 m high

A mountain rises to a height of morethan 600 m above the Earths surface


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Contour Patterns and Physical Features

Valley

Contours point towards higher ground, formingan inverted V from the top to the bottom.

Streams or rivers found in valleys are drawn as

blue lines on maps.


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Plateau

A plateau is an upland area

It has steep slopes and a flat summit


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Ridge

A ridge is a linear or elongated upland area

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Interpreting the Human Environment Shownon a Topographical Map

The human environment consists of human features

such as roads, buildings and plantations.Settlements

Usually represented by black squares or rectangles on maps

Using symbols, map makers are able to show the shapes andsizes of settlements and their distribution

By looking at a map, it is possibleto find out why a settlementhas grown at a certain site

I t ti th H E i t Sh


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Transport networks

Roads, railways and canals are shown on maps as lines Roads are usually represented by red lines

Railways are usually represented by black lines

Canals are usually represented by blue lines

Locations of roads and railways are often affected by therelief of the land

Most maps reveal therelationship between thelocation of roads andrailways to the locationof settlements

I t ti th H E i t Sh


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Land use

Maps provide a picture of the land use in an area By checking the symbols used on the maps against the legend,

we can find out the types of crops grown, the amount of landunder cultivation, and the presence of any agricultural as wellas industrial activities


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Understanding Physical and HumanEnvironments Shown on a Topographical Map

We can interpret the environments on a topographical

map systematically by using the questions below:

Is the land steeply sloping or gently sloping?

What are the main physical features in this area?

Where do people live?

Why do people live where they do?

How well connected are the settlements by

transportation?

What are the human activities carried out in the place?

Skill B ild S t d A


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Skills Builder: Suggested Answer


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Additional Resources from Multimedia TEACH Resources

Photo Bank

Photo 5-1The desert hills ofthe Capitol Reef

National Park aregently-sloping. Ona topographicalmap, these hills are

represented bywidely-spacedcontour lines.


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Photo Bank

Photo 5-2A plateau (in the background) in Bruce Canyon NationalPark is characterised by steep slopes and a flat top.


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Photo Bank

Photo 5-3

The contours of this steep-sided rock cliff would

be closely spaced on a topographical map.

interpreting topographical maps

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