Globes and Maps

 

What Is Globe?

A small man-made model of the earth is called a globe. A globe is a simple and accurate way of representing the earth. that appeared on the cover


The maps on the globe show the correct size, shape and location of the places in relation to each other. However, a globe has the following limitations:

It is difficult to carry a globe. 

The space on the globe is limited and details cannot be shown on it.

 A globe cannot be made for a part of the earth.

Details of the geographic features cannot be shown properly. 

It is not only difficult to make a big size globe, but also difficult to handle it.

What is Map?

A map is the representation of the earth as a whole or a part of it, drawn to a scale on a flat surface. Although less accurate than a globe, a map is more useful.


The word map has been derived from the Latin word 'mappe meaning napkin, Mercator and Hondt were the first to publish a collection of maps in the form of a book. Its cover had the picture of the Greek mythological giant Atlas,holding the earth.Since then book of Maps is called an atlas.

Types Of Maps

Maps are useful for learning and understanding  the various features present on the surface of the earth. Different types of maps are used by different people according to their needs.


Maps can be classified in many ways, but two of them are most useful. One classification is based on the scale of the map and the other is based on the function of the map.


According to scale, there are two types of maps-small scale maps and large scale maps.

 Small scale maps show a very large area with less details. The maps in an atlas or the wall maps used in classrooms are small scale maps (See Map 2).


Large scale maps show a very small area in detail. The layout maps of villages and the guide maps of cities are large scale maps (See Map 3). 

According to function, there are three main types of maps-physical maps, political maps and thematic maps.


Physical maps show the relief features present on the earth's surface like mountains, hills, plateaus, plains, peaks, valleys, rivers, oceans, etc. These maps help us to find suitable sites for human settlement, for building roads and railways and for the construction of dams, etc.


Political maps show the boundaries between different countries and the boundaries of different political units within a country. These maps are used as base maps for showing various cultural. historical and economic activities.


Thematic maps show specific type of information, such as roads, railways, ait routes, distribution of population, conditions of climatic elements, location of mining and industrial centres, etc. The title of the map is given according to the information given on the map.

There are three main components of maps They are distance, direction and conventional ng signs or symbols. The direction of a place with  respect to the north and the distance between any two places are essential features of a map.


MEASURING DISTANCES

 Distance means the space between any two places. Distances can be long or short. We normally say that the market is near our house and the school is far-away. Near means that we can reach a place in a short time, while far away means that we need more time to reach that place. Thus, distance is related to the time taken to reach a destination. However, the time taken to cover a given distance varies not only from person to person but also from place to place. Thus, we need a system to measure distances accurately.

In India we follow the metric system, in which long distances are measured in kilometres (km) and short distances in metres (m). The distance between any two points on a map is measured in centimetres (cm). We normally measure the straight-line distance.

We measure the distance between any two places on the map and relate it to the distance between the same two places on the ground.

The distance between any two places on a map, measured along a straight line, is called the map distance. 

* The distance between the same two points on the ground, measured along a straight line, is called the ground distance.

The ratio between the map distance and the ground distance is called the scale of the map.)

Suppose, the scale of a map is 1 cm: 1 km. This means that a distance of 1 cm between two points on the map corresponds to a distance of 1 km between the same two places on the ground.


How to show Scale on a Map?

The scale on a map can be shown in the following ways:

By a Statement in the statement method,the scale is given in words, such as one centimetre is to two kilometres or 1 am: 2 km. In this statement, 1 cm is the map distance and 2 km is the corresponding ground distance. This is a quick method of using the scale for showing distances.


By a Numerical Fraction The numerical fraction method is also called representative fraction or R.F. In this method, the ratio between the map distance and the ground distance is given as a fraction whose umerator is always one.


The R.F. is given as 1/1,00,000

 In this example, the numerator (1) represents the map distance and the denominator (1,00,000) represents the ground distance. 

Thus, R.F.= Map distance/Ground distance

 No particular units of measurement are used with R.F. It has the universal application in map making.

 By a Graphic or Linear Scale In the graphic or linear scale method  the map distance is shown with the help of a straight line.. The line is divided into parts called primary divisions. The first primary division is further subdivided into secondary divisions.

The linear scale helps in showing the distance directly from the map. It also gives the values of the corresponding ground distance.


 FINDING DIRECTIONS

 The direction is shown on a map with the help of an arrow. Its tip is marked with the letter N This means that the arrow is pointing towards the north. The arrow on a map is called the North line.


The directions on the map or on the ground are always shown with respect to the north we know the north, then it is easy to find other directions, namely south, east and west These are the four cardinal directions on a map.

Once the four main directions are marked, we can easily find the intermediate directions. The direction midway between north and east is called the north-east (NE). Similarly, other three intermediate directions are south east (SE), north-west (NW) and south-west (SW) (See Fig. 4.2)


How to find the Direction?


An easy and quick way to find the direction is by facing the rising sun or with the help of the pole star. We know that the sun rises in the east sets in the west. If we stand facing the in the morning, then we face the east. west is towards our back. The left hand points towards the north and the right hand points towards the south (See Fig. 43).

A magnetic compass is also used to find the north.The needle of the magnetic compass always points towards the north-south direction. This compass is also called the mariner's compass, as it is used by mariners or seamen to find the direction while sailing .

The Pole Star is located vertically above the North Pole. In the Northern Hemisphere, the constellation known as the Great Hear scalled the Saptarishi in Indiat keeps revolving around the Pole Star. The two pointer stars of the Great Bear always point towards the Pole Star (See Fig. 4.4)


CONVENTIONAL SIGNS AND SYMBOLS 

Maps are used for recording and showing a variety of information, such as political boundaries, relief features, climatic conditions, distribution of resources, population, means of transport, social and cultural features, cities and towns, etc

if north is not shown on a map, the top of the map is taken as the north and the bottom as the south When you stand facing the map, the right hand side is the sast and the left-hand side is the west.

There is not enough space on a map to shen the actual size and shape of features such as mountains, peaks, rivers, lakes, bridges, dams, forts, forests, temples, churches, railway tracks and airports. However, a map without these features will be less informative. Thus, different colours, signs, symbols and letterings are used to present the information on the map. To understand the information given on a map, it is necessary to learn and follow the signs and symbols used in it. These signs and symbols keep the map clean and thus makes it easy to read .

There is an agreement among many countries of the world about the common use of signs,symbols and colours.For example  blue is always used to show water bodies and green is used for the plains.Thus these signs and symbols are called conventional signs and symbols.

The information shown on a map can only  be read and understood by those who know it language, which includes features like sale directions, colours, signs and symbols.


SKETCH


Suppose we want to help a new student in the class to locate and reach the neighbourhood bookshop. We would draw a rough diagram of roads to show where to turn and which landmark to look out for in order to reach the bookshop. With this rough diagram, the new student can reach the bookshop easily, even though the exact distance and directions are not mentioned. Such a diagram, which is drawn without measuring the distance between the various places, is called a sketch.

Thus, a sketch is a rough map with outlines, drawn without a scale and also without the proper use of signs and symbols.


PLAN


Sometimes, we want to draw an accurate map of a very small area like that of a house or a building. For example, if you and your family want to shift to a new house, it would be useful to have an accurate map of the house. This is also called a layout plan.

This layout plan will show the length and the breadth of each room in the house, the height of windows and doors, etc Such an accurate map of very small area, which shows even the minor details, is called a plan. A plan is always drawn according to scale. The scale of a plan is different


from that of a map.Generally a map represents a large area .so it is drawn on a small scale  1 cm on a plan may represent just 1 m on the ground.

On the other hand, a plan represents a very small area, and is therefore drawn on a large scale. 1 cm on a plan may represent just 1 m on the ground.

Thus, to sum up we can say: 

A map shows either a large area without details or a small area in detail.

A plan shows a very small area in great detail.

A sketch is a rough diagram drawn without a scale.

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