1. Map Scales and Measuring Distances
1 Star Map and Compass
Lesson 4

2. Write down the names of these symbols
Revision
Conventional Signs
Write down the names of these symbols
1 – Station (Railway)
2 – Public Telephone
3 – Place of Worship with Tower
4 – Parking
5 – Wind Pump; Wind Generator
6 – Castle/Fort 1 2 3 4 5 6
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3. What is the 6 figure grid reference of the following?
Revision
Grid References
Write down the two rules you need to remember when doing grid references.
What is the 6 figure grid reference of the following?
The Inn
Halt Train Station
The Letter B
Write down the two rules you need to remember when doing grid references.
a. A reference must always contain an even number of figures.
b. A count must always be made first along the lines from west to east, and then from south to north.
What is the 6 figure grid reference of the following?
The Inn – 765/327
Halt Train Station – 760/323
The Letter B – 767/329
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4. The Aim
The aim of this lesson is to teach you how to measure distance between two points on a map so that by the end of the lesson you will be able to work out how far your walking on your expedition.
The aim of this lesson is to teach you how to measure distance between two points on a map so that by the end of the lesson you will be able to work out how far your walking on your expedition.
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5. Scales 1 :
One on the map = One on the ground 1 : 1 : 2 1 : 2
One on the map = Two on the ground 1 : 4 1 : 4
Because it is impossible to make a map the same size as the country which it represents, everything on the map has to be reduced, i.e., scaled down in a fixed proportion. The scale of a map is the proportion which the distance between two points on it bears to the distance between the same two points on the ground. Thus, when comparing two map sheets, each of exactly the same size, one might show the whole of England and Wales while the other might show only a small district. In other words, the scales of the two maps would be different.
The method of expressing a scale is as a representative fraction (RF). For example, the representative fraction 1:50,000 (the scale of the map most frequently used) means that one centimetre on the map represents 50,000 centimetres on the ground, and one metre on the map represents 50,000 metres (50 kilometres) on the ground. The representative fraction 1:25,000 (the scale of the map sometimes used) means that one centimetre on the map represents 25,000 centimetres on the ground and one metre on the map represents 25,000 (25 kilometres) on the ground.
One on the map = Four on the ground
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6. Questions? Scales 0105MAC04PP How are scales represented?
Representative Fraction (RF).
On a 1:25,000 Map. 1cm on the map is how many centimeters on the ground?
25,000 cm
A 1:50,000 map shows more or less detail than a 1:25,000?
Less.
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7. Measuring Distance To measure the distance along a straight line
Take a strip of paper
Place the corner on the first point and line up the second B
To measure a straight line distance between two points lay the straight edge of a piece of paper against the two points and at each point mark the paper with a dash.
Strip of Paper
Draw lines to show where the points are A
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8. Line it up and read off the Distance
Measuring Distance
To measure the distance along a straight line
Distance = 2.2Km
1 Km 1 2
3 Km
Then take it to the scale at the bottom of the map
Then lay the paper along the scale line at the bottom of the map with the right hand dash against one of the major divisions so that the
left hand dash lies against the sub-divisions to the left of the zero mark. The total distance is then the number of major divisions plus the distance to the left of the zero mark.
Strip of Paper A B
Line it up and read off the Distance
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9. Measuring Distance
Questions?
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10. Measuring Distance To measure the distance along a road or a river
Strip of Paper
To measure the distance along a road or a river
Strip of Paper A
Take a strip of paper
Place the corner on the first point and line up the first bend
Strip of Paper A
Strip of Paper A A
To measure the distance along a road or a river which is not straight, lay a piece of paper along the first section and mark it with a dash at the start and end of that section. Then pivot the paper about the second dash until it lies along the second section and repeat the process, and so on, until the last point is marked.
Strip of Paper
Draw lines to show where the points are B
Keep doing this
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11. Line it up and read off the Distance
Measuring Distance
To measure the distance along a straight line
Distance = 3.0Km
1 Km 1 2
3 Km
Then take it to the scale at the bottom of the map
The total distance along the road is then recorded as a straight line on the piece of paper and can be read off against the scale.
Strip of Paper A B
Line it up and read off the Distance
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12. Questions? Measuring Distances 0105MAC04PP
On a 1:50,000 Map. 1cm on the map is how many centimeters on the ground?
50,000 cm
What do we use to measure distance on a map?
Scrap of paper and the scale
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13. Summary Measuring Distances 0105MAC04PP
There you have learnt how to effectively measure distance on a map.
Look forward to North Points.
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14. Measuring Distances
END
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