## Definition

**- Map** - representation of the whole or part of the earth’s surface drawn to scale.

- Shows outline of objects on the ground
- Drawn as if the drawer was above the ground
- It shows details
- Most of the features are indicated by symbols.

**- Picture**: image of a real object.

- Gives details in their visible shapes and sizes
- Can be inform of free hand, drawing, painting or a photograph
- Not drawn to scale

**- Plan:** outline of something drawn to scale.

- Also drawn as if a person was directly above the ground
- It represents a very small place
- The scale is large to show details e.g. house plan
- Gives specific information

## Types of Maps

- Classified according to the purpose for which each map is drawn.
- Topographical Maps: This shows selected natural physical features on a small portion of a country.
- Atlas maps: this is a collection of maps in one volume.
- Sketch maps: maps which are roughly drawn. A good sketch map should have the following characteristics:
- neat and clear
- title
- frame
- key
- compass direction

## Uses of Maps

- Sketch maps are used to summarise information for easy reference.
- Used for locating other countries.
- Used for comparing sizes of countries.
- For locating climatic regions of different parts of the world.
- Give information on distribution of geographical phenomena e.g. vegetation on the earth’s surface.
- Help travellers to find their way.
- Used to calculate distance of a certain place.
- Used to locate physical features like landforms.

## Marginal Information

- Information contained in the area surrounding the map.

- Map name e.g. Yimbo.
- Sheet title e.g. East Africa 1:50000 (Kenya).
- grid system numbers
- latitudes and longitudes
- Compass direction with grid, true and magnetic north.
- scales
- key
- publisher and copyright
- Map identification
- Map series
- Sheet number or sheet index
- Sizes of Scales

## Map Scales

- A scale is a ratio of a distance on a map to a corresponding distance on the ground.

### Types of Scales

- Statement scale –expressed in words e.g. 1cm represents 1km, 1cm to 1km.
- Representative Fraction (RF)-expressed as a fraction or ratio e.g. 1/200,000 or 1:200,000.
- Linear scale-shown by a line which is subdivided into smaller units.

### Conversion of Scales

#### Statement Scale into RF

**1cm rep 1km to RF**

- Multiply the number of kilometres by 100,000 (1km=100,000cm) i.e. 1×100000=100,000.
- Statement scale is
^{1}/_{100,000}or 1:100,000.

**2cm rep 1km**

- Divide both sides by two to get 1cm rep ½ kilometres.
- Multiply ½ by 100,000 to get 50,000.
- RF is
^{ 1}/_{50,000}or 1:50,000.

#### RF to Statement Scale

- Divide the denominator by 100,000.
- Write the scale in statement form.

#### Linear Scale to Statement Scale

- Measure a unit distance off a linear scale e.g.

- The distance is 4-3=1km which is represented by 2cm.
- Use the methods in (1) and (2) above.
Q. Given that the ground distance is 200km while the distance on map is 20cm calculate the scale.

### Sizes of Scales

- Small scales- show a large area of land on a small size of paper. They show limited details e.g. 1:250,000, 1:500,000, 1:1,000,000.
- Medium scales- used to represent a relatively smaller area on a given size of paper e.g. 1:50,000, 1:100,000, 1:125,000.
- Large scales-used to represent a small area of land on a given piece of paper. They show a lot of details e.g. 1:2,500, 1:10,000, 1:25000

### Arranging Scales in Order

- Ascending Order-smallest to largest
- Descending Order-largest to smallest

(1)1/500,000

(3)1:25,000

(4)1/10,000

(2)1cm rep 500m

### Uses of Scales

- Estimating distances on maps
- Measuring distances accurately-use dividers and ruler, piece of string or thread for curved distances or straight edge of paper.

E.g. calculate actual distance of a line 8.5cm long on a map using the following scales.

(i) 2cm rep 1km

(ii) 1:100,000 - Calculation of areas-no. of full grid squares+ number of ½grid squares/2 or use of rectangles (l×b) or triangles (½ b×h).

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