Components of a Map

Map reading is the process of examining the given topographical map, conventional symbols and signs.

Map interpretation is the process of examining a given topographical map of an area represented for identifying the geographical information of an area.

Map Work is the study and analysis of maps, especially prior to, or in relation to fieldwork

1. Sketch map
2. Atlas map/ wall maps
3. Topographical maps

Sketch Maps

A map drawn from observation (rather than from exact measurements) and representing the main features of an area.

Atlas Map / wall map

A collection of different maps that have been bound together in one volume to form a book. These maps are usually drawn to scales example shows town and cities, hills, mountains, valleys, forests, countries, etc.

Topographical Maps

Shows selected physical and human features in an area and their positions on the ground for example hills, village, mountains, lakes, ponds, rivers

A topographical map

A map is good if it contains all the essentials of maps, therefore the essentials are good qualities of maps.

The essentials of a good map are:

1. Key. Used to interpret symbols and signs found on a map. They appear in a box at one of the bottom corner of the map.
2. Title. Used to show what's map is all about. This is the heading of the map. It can appear on top of the map or anywhere else
3. North direction. This is an indication of the north direction. It shows where north is and by knowing north one can know the direction and bearing of the place.
4. Margin. This is a boundary or limit around the map. It gives or shows the reader and interpreter the end of the map.
5. Scale. It shows the relationship between map distance and the actual ground distance for example 1cm to 10km means one centimeter on the map represents ten kilometers on the ground
6. Latitude and Longitude / Grid Reference. It used to locate the place on the map. For example, the map of Tanzania is located at latitude 6°00' south of the equator and longitude 35°00' east of Greenwich meridian.
7. Publisher and date publication. This shows when the map was produced and a publisher.

Information on a map is represented using symbols and signs. These are called the alphabet of maps. With the aid of a key, one can interpret or read a given map. Symbols usually look like the features they represent, but signs do not. Most of the symbols are pictorial whereas signs are conventional. A conventional sign is a standard symbol used on a map and explained in the key to show a definite meaning. For example, a dot represents a town or settlement. Signs and symbols are used to improve the reading and interpretation of maps. Various symbols are used to represent features such as buildings, mines, forests, rivers and lakes. Features may be represented using colours of the actual features. For instance, vegetation is represented using green whereas water is represented using blue

Some of the symbols used on maps

Some of the signs used on maps

Is the relationship or ratio between map distance and actual ground distance.

Scale = Map distance / Ground (actual) distance.

Types of Scale

We can classify the scale according to the size in our criteria. There are three types of scales;

1. Large Scale They are used to present information on small areas for example a map of village buildings and farms. The map size involves all numbers less than 1:25000 i.e. 1:10000 and 1:5000 Characteristics of large scale.
   1. It has smaller numbers in the denominator.
   2. It shows features clearly
   3. It contains geographical details.

Distribution of continents

2. Medium Scale They are used to represent medium details shown on the map. i.e. 1:50,000 and 1:100,000. Example of a map that can be drawn using medium scale is a map of a district, region, city etc.

Administrative unit of Dodoma district

3. Small Scale They are used to present information that is long. This type of scale covers a big area with less detail. For example a map of a country, continent or world. May involve numbers between 1 : 500,000 to 1 :1000,000

A map of a school

Characteristics of small scale

1. It has the largest denominator.
2. Contains a lot of geographical information.
3. It does not show geographical features clearly.

Ways Used to Express Map Scale

1. Statement Scale Refers to the scale, which is expressed in terms of words or explanation. For example, one centimeter on a map is equivalent to 10 centimeters on the ground.

2. Linear Scale This is a line, which is divided into two parts. The primary division and secondary division. The secondary are expressed in meters and placed on the left side from zero and primaries are expressed in kilometers and placed on the right side from zero.

A linear scale

3. Representative Fraction (RF) Scale Is written as a fraction or ratio eg. 1:50,000 50,000 The distance on a map is expressed as fraction of the actual distance on the ground. Therefore, RF scale = map distance Ground distance. The top number (numerator) represents the map distance on the ground and is usually more than

Scale Conversion

1. 1:50,000 convert into statement scale 1 KM = 100,000 CM Take the denominator (50,0000) divide by 100,000 (actual number in a km) 50,000 / 100,000 = 0.5 KMThus, One centimeter to half kilometer (1cm to 0.5km)
2. To change statement to R.F scale 1cm represents 60km 1km=100000cm

60km= x 1:6000000 Therefore R.F scale = 1:6000000

Importance of Scale on the Map

1. Scale help to calculate area of a map
2. It enable us to calculate distance on a map
3. Scale shows the relationship between map distance and the actual ground distance
4. Scale help us to enlarge and reduce the area on a map or the whole map
5. Scale can be used to calculate the vertical exaggeration on a map
6. Scale is used to calculate the gradient on a map