## Scale

A scale is the relationship between the measurement on a map and the measurement along the ground.

A scale is used to reduce the real distance along the ground so that this distance may be drawn on a small sheet of paper.

Every map has a scale, which enables us to understand how big something is in real life.

For example, if the scale of the map was 1 cm = 1 km that means that a line on the map which is 1cm long is showing something which in real life measure 1 kilometre (which is 1,000 metres, or 100,000 centimetres).

A scale of 1:50000 (say 1 in 50000) means that 1 cm measured on a map is equivalent to 50000 cm along the actual ground. That is 1 cm equals 1/2 kilometre.

A scale is used to reduce the real distance along the ground so that this distance may be drawn on a small sheet of paper.

Every map has a scale, which enables us to understand how big something is in real life.

For example, if the scale of the map was 1 cm = 1 km that means that a line on the map which is 1cm long is showing something which in real life measure 1 kilometre (which is 1,000 metres, or 100,000 centimetres).

A scale of 1:50000 (say 1 in 50000) means that 1 cm measured on a map is equivalent to 50000 cm along the actual ground. That is 1 cm equals 1/2 kilometre.

## Types of scales

A map scale are general presented in three ways.

(1)

(2)

In this example, one centimeter on the map equals 250,000 centimeters or (2.5 kilometer) on the earth. It can also means that one inch on the map is equal to 250,000 inches on the land, that is, (20833 feet, 33 inches or about 3.95 miles).

100 cm = 1 m

100000cm = 1km

1000m = 1km.

63360 inches = 1 mile

5250 feet = 1 mile.

To convert this to RF you simple multiply 1km by 100000cm (1*100000 = 100000). (remember that 100000cm = 1km) So the RF is now = 1:100,000;

Example (1) RF is 1:250,000

To covert this Rf to word scale you need to remember that 1000m = 1km and that 100cm = 1m.

You then divide 250000 by 100cm then divide this answer by 1000m. (250000/100cm = 2500m /1000m = 2.5km)

or you just divide 250000 by 100000cm. (250000/100000=2.5km)

(3)

Watch the following videos about maps scales.

http://www.youtube.com/watch?v=iYsUgrD5Qu8

http://www.map-reading.com/ch5-1.php

http://www.map-reading.com/ch5-2.php

(1)

**A word statement**- This gives a written description of map distance, such as "One inch equals four miles" or "One centimeter equals ten kilometers."(2)

**A ratio or representative fraction**(RF) indicates how many units on the earth's surface is equal to one unit on the map. It can be expressed as 1/250,000 or 1:250,000.In this example, one centimeter on the map equals 250,000 centimeters or (2.5 kilometer) on the earth. It can also means that one inch on the map is equal to 250,000 inches on the land, that is, (20833 feet, 33 inches or about 3.95 miles).

**Points to Remember**100 cm = 1 m

100000cm = 1km

1000m = 1km.

63360 inches = 1 mile

5250 feet = 1 mile.

**Converting Word Scale to RF****Example (1)**1 cm to 1kmTo convert this to RF you simple multiply 1km by 100000cm (1*100000 = 100000). (remember that 100000cm = 1km) So the RF is now = 1:100,000;

**Example (2) 1 inch to 4 miles****Remembering that 63360 inches is equal to 1 mile you simple multiply 4 miles by 63360 inches. ( 4*63360 = 145440)**

**The RF is now 1:245440****Converting RF to Word Scale**Example (1) RF is 1:250,000

To covert this Rf to word scale you need to remember that 1000m = 1km and that 100cm = 1m.

You then divide 250000 by 100cm then divide this answer by 1000m. (250000/100cm = 2500m /1000m = 2.5km)

or you just divide 250000 by 100000cm. (250000/100000=2.5km)

**The Word Scale is now 1 cm to 2.5 km.**(3)

**A linear scale**(bar scale, scale bar, graphic scale, or graphical scale), is a means of visually showing the scale of a map. It is divided into equal portions, that is used to show the relationship between a distance on a map and the actual distance on Earth. it is the most accurate of the three types of scale. Graphical scales can be stated in kilometres (metric) or miles (imperial)Watch the following videos about maps scales.

http://www.youtube.com/watch?v=iYsUgrD5Qu8

http://www.map-reading.com/ch5-1.php

http://www.map-reading.com/ch5-2.php