Geography

Key unit competence

By the end of this unit, I should be able to explain the relationship between the

physical and human activities on maps

Introductory activity:

A map is a representation of all or part of existing things on the earth surface on a flat surface. A photograph is a picture of an object or environment taken by a camera at a particular time in a given place. Maps and photographs represent both physical and human features. The aspects represented on map/photographs are shown using several types of signs and symbols. This helps map /photograph users to extract the needed information from a given map /photograph.

Referring to the map above and the definition above;

a. Identify the main physical features represented on the map.

b. Identify the human features represented on the map.

c. Use the following map to represent approximately the same features as

those represented on the map above. 

d. Take a photograph of the environment around your school and then identify all physical and human aspects taken on that photograph.

3.1. Interpretation of physical aspects from maps/photographs

Activity: 3.1

Make a research on:

a. The major physical aspects which may be represented on a map/

photograph.

b. The signs and symbols which may be used to represent physical

features on a map/photograph.

Physical features are also called natural features. They include the following:

– Relief which comprises rocks, slopes, soils, valleys, plains, plateau, hills and

mountains.

– Drainage features like rivers, dams, lakes, seas and oceans.

– Vegetation cover like forests made of several types of trees, crops and ground

vegetation, wetland vegetation.

– Climate which is defined through various parameters like rainfall, temperatures,

relative humidity, cloud cover, wind speed and direction, atmospheric pressure,

sun shine.

The following are the most commonly used methods to represent the selected physical features:

3.1.1. Interpretation of geological features

The main geological features commonly represented on a map/photography

include rocks, cliffs and boulders.

– A rock is a solid matter which is found on the surface or in the interior of the

earth.

– A cliff is a vertical or nearly vertical rock face in mountainous and hilly areas.

Cliffs are found along the shores of lakes and seas. Cliffs and rocks are shown

on topographical maps using contours that are close to each other. Boulders

are large pieces of rock. They indicate weathering and mass wasting taking

place on the cliff.

– Flat rocks show the eroded and exposed rock on the seabed where the shore

is shallow or found the bed of a river or within the dry valley.

– A crater is a bowl-shaped depression, or hollowed-out area, produced by the

impact of a meteorite, volcanic activity, or an explosion.

– A quarry is a place from which dimension stone, rock, construction aggregate,

riprap, sand, gravel, or slate has been excavated from the ground. A quarry appears like a place where open cast mining is practiced.

3.1.2. Interpretation of slopes from a map/photograph

The slopes are classified according to their inclination, constancy or shape. The slopes are represented on the map by help of contours. Contours are lines on a map linking places of the same height above the sea level. They are drawn at fixed intervals, known as vertical interval or VI. Contours are labeled from the lowest to the highest. Where they are too close to each other, the relief is steep. Where they are far apart, the land may be a plain or a plateau. The main types of slopes are: gentle, steep, regular, irregular, convex and concave slopes.

– Gentle slopes: Spaced contours are used to indicate gentle slopes. In that

case the land may be a plain or plateau.

– Steep slopes: Very close contours are used for steep slopes. The closer the

contours, the steeper the slope. In that case the landform may be a mountain.

– Regular slopes: Regular slopes are also called constant or even slopes. The

contours have constant spaces. The slopes can be either gentle or steep slopes.

– Irregular slopes: These are uneven or inconstant slopes. They are represented

by unequally spaced contours. They can be either gentle or steep slopes. These

slopes are found mostly in rugged, mountainous or hilly areas. 

– Concave slopes: They indicate that the land is steeper on the upper part and gentler on the lower part. They are drawn using closely packed contours on the upper part of where the slope is steep. The contours are widely spaced on the lower part where the slope is gentle.

– Convex slopes: Convex slopes are gentle at the top and steep at the bottom of the hill or mountain. The contours are closely spaced at the bottom section (steep slopes) and widely spaced at the top section (gentle slopes).

3.1.3. Interpretation of drainage and landforms from a map/photograph

i. Interpretation of drainage features from a map/photograph

The lake, sea and ocean occupy a very large area. They are seen in blue color on a color photograph and in dark color on black and white photograph. However other conventional symbols may be applied on a map to represent a lake, sea and ocean; the most important thing is to put in legend/key the used symbols.

The rivers originate from mountains or hills and flows on steep slope to end in the depression that are usually found in valleys or low-lying areas. The streams and rivers are seen on a photograph/map as lines and they have different patterns or arrangements which can be detected easily on a map or photograph.

ii. Interpretation of landforms:

 – Valley: A valley is an elongated depression sloping towards a drainage basin like a sea, lake or swamp and which may contain water or not. The valley is normally represented on a topographic map by using the contours having “V shape”.

– Plain: Most of the plains are in low-lying areas but some of them may be raised but the slopes remain gentle. On the topographical maps, a plain is represented by widely spaced contours. The river passing in plain areas may also be shown on the map.

– Plateau: A plateau is an extended landform which is bordered by steep slopes. On the map, a plateau is shown as a wide area surrounded by one or two contours having the same height on both sides.

– Mountain: A mountain is an extended landform with steep slopes. On the map, a mountain is shown as a wide area with very close contours surrounded by one or two wider contours showing the depression areas surrounding the mountain.

3.1.4. Interpretation of soils on the map

Assorted colours or symbols are used to show several types of soils on a topographic map. Tiny brown dots called stipples are used to represent a surface covered by sand or mud. The types of soil can be also shown by help of dots having varied sizes according to the texture of the soil. The types of soils can be differentiated on a photograph based on their texture (sizes) and color. Surfaces covered by lava flows are shown by symbols that look like inverted V’S.

Application activity: 3.1

a. Identify the physical features in area where you live and describe how

they are represented on a topographic map.

b. Draw a sketch of your home area on it name and mark the physical

features identified in (a) above.

c. Suggest ways through which the above features can be protected

and conserved.

3.2. Interpretation of human aspects on maps

Learning activity: 3.2

Make a research on:

a. The major human aspects which may be represented on a map/

photograph.

b. The signs and symbols which may be used to represent human

features on a map/photograph. 

Human aspects on a map reflect human activities of a given area represented on a map. These include agricultural development, mining, industry, settlement, etc.

3.2.1. Agricultural activities 

Crop plantations are drawn on a topographical map by using light-green shading. A letter may be used over the shade to indicate the name of the crop growing in each area. For example, C for coffee; T for tea.

3.2.2. Mining and quarrying activities from a map

Mining refers to all the processes by which minerals are obtained from the earth’s crust. Minerals may be in gaseous, liquid or solid form. Quarrying is the digging of stones, sand or soil from the ground. These are used, for example, in construction. Mining and quarrying activities on a map are shown by symbols as represented on the figure below. The mining activities may be taken on a photograph and different types of minerals/quarries may be differentiated based on their colors.

3.2.3. Industrial areas

 Industrial area is a geographically localized set of specific industries. Such areas are subject to important production, marketing and other interrelationships.

3.2.4. Settlements 

Settlement refers to a place where people live. It also means the process of settling in such a place. Settlement on the map can be shown by dots or rectangles which may be black or grey in colour. Dots indicate rural semi-permanent settlements while rectangles show permanent buildings like those built of stone or bricks, with iron or tile roofing. The dots or rectangles are spaced in relation to the concentration of settlement. Nucleated settlements are represented by the dots and rectangles close to one another while they are much spaced for scattered settlement.

The settlement is also represented according to its shape, for example ring or linear. The shapes of settlement may be influenced by communication networks like roads, railways, landforms like valley, plain, plateau, mountain among others.

Application activity:3.2

1. Use a photograph/map to identify and describe mining/quarrying areas.

2. Visit the nearest mining/quarrying areas and represent them on sketch

map using appropriate signs and symbols.

3.3. Relationship between physical and human aspects on maps photographs

Physical aspect of an area plays a key role in the activities people do. It also has an influence on the number of people who settle in an area. For instance, the relief affects human activities in the following ways:

– Mountainous places are less populated because of steep slopes being unfavorable for settlement and for mechanized agriculture. Such landscape makes the establishment of social facilities (hospitals, schools, shopping

centers) in such places to be difficult.

– Places that are poorly drained like swamps and marshes are also not suitable

for settlement.

– Some plains and plateaus have good soils. These allow growing of crops and

keeping of livestock. It is also possible to use machines in farming. There is no

need to make terraces to stop soil erosion. Therefore, more food is produced,

and more people live there.

– The depressions or valleys areas are also suitable for agriculture.

– Fishing is done in seas, oceans and lakes.

3.3.1. Drainage patterns

 A drainage pattern is a network formed by rivers and their tributaries on the landscape. The development of the drainage patterns is influenced by the gradient of the slope, nature of the bedrock in terms of hardness, structure of the basement rock. The drainage pattern can also result from human activities which may change the original patterns. Man’s activities that have direct impact on the drainage pattern include agriculture, industries, settlements, dam construction, etc.

The main drainage patterns which can be seen on a topographic map/photograph

are as follows:

– Trellised drainage pattern: Such patterns are developed in simple folds

characterized by parallel anticlinal ridges alternated by parallel synclinal

valleys.

– Dendritic drainage pattern: The dendritic pattern is associated with the

areas of similar lithology, horizontal or very gently dipping strata, and rolling

extensive topographic surface having extremely low reliefs.

– The rectangular drainage pattern is generally developed in the regions

where the rock joints form rectangular pattern. The rocks are weathered and

eroded along the interfaces of joints, fractures and faults and thus surface

runoff collects in such long and narrow cliffs and forms numerous small rills.

– Radial drainage pattern also known as centrifugal pattern is formed by the

streams which diverge from a central higher point in all directions. 

– Centripetal drainage pattern: This pattern is formed by a series of streams

which after emerging from surrounding uplands converge in a central lowland

which may be a depression/basin/crater lake

– Annular drainage pattern: The annular drainage pattern, also known as

“circular pattern”, is developed over a mature and dissected dome mountain

characterized by a series of alternate bands of hard and soft rock beds.

– Barbed drainage pattern is formed when the tributaries flow in the opposite direction to their master streams.

– Herringbone drainage pattern also known as rib pattern (like the limbs of human beings) is developed in mountainous areas where broad valleys are flanked by parallel ridges having steep hillside slopes.

– Parallel drainage patterns comprise numerous rivers, which are parallel to each other and follow the regional slope. This pattern is more frequently developed on uniformly sloping and dipping rock beds such as cuestas or newly emerged coastal plains.

3.3.2. Settlement patterns

 Settlement refers to a place where people live. It also means the process of settling in such a place. The settlement patterns of a given area are influenced by both physical and human factors like topography, road network, community services, cultural and economic factors, etc. This results into several types of settlement patterns as follows:

– Nucleated settlement: This refers to the grouping of many houses around a center called nucleus; often around a central feature like a church or a pub. Houses are built close to each other. This type of settlement is mainly influenced by cultural and social factors. For example, the houses in “imidugudu” settlements may have such pattern.

– Linear settlement: This is where houses are well planned. They are built along the road, railway and river or along the coast.

– Sparse or scattered or dispersed settlements: These settlements are associated with houses which spread out over a wide area (houses are built far from each other). They are often the homes of farmers and can be found in rural and mountainous areas.

– Isolated settlement: This is where a few people live away from other people.

These people could be hunters in a forest.

– Ring settlement: In this type of settlements, houses make a circle. There is an

open ground at the center.

– Planned settlement: This type of settlement is well organized and planned in specific ways as directed for instance by the government.

3.3.3. Vegetation

 Human activities are related to vegetation. The distribution of vegetation on a photograph/map in each area is linked with human activities taking place in that part/dwelling. Below are some of the examples that show the interrelationship between man and vegetation.

– In areas with dense forests: The main activities are timber harvesting. The timber is used to make furniture and paper.

– In savannah grasslands: the main activities are livestock keeping and agriculture. This is because in these areas soils are fertile.

– Desert vegetation: Agriculture is only possible in oases. Very few animals can survive in the dry areas like the camels, goats and sheep and reared under nomadic pastoralism.

– In tundra and taiga forests: The low rainfall and temperature affect human activities. Only hunting, fishing and mining are the main activities done in these regions.

3.3.4. Communication networks 

Communication networks facilitate the movement of people and commodities from one place to another over a given distance. Communication networks may also refer to the physical facilities which help the transmission of information in the form of news and messages. The communication networks represented on map/ photograph are most of time influenced by both physical and human factors. Some of them are discussed below:

– Relief: Steep slopes make the construction of roads and railway lines expensive. On the other hand, valleys have swamps; they contain water logged soils that are too soft to allow the movement of heavy objects like trailers, lorries and trains.

– Climate: Too much rainfall results into floods and landslides and these disturb land transport. On the other hand, accumulation of fog and clouds reduce visibility hence affecting air transport.

– Drainage: Navigable rivers, lakes, seas and oceans provide natural route-ways used for transportation.

– Economic activities: The economic activities (mining, agriculture, industries, etc) taking place in given areas influence the construct of communication networks.

Application activity: 3.3

1. Identify several types of communication networks on any map/

photograph.

2. Explain how the identified communication networks are related to

physical and human features.

3. Move around your village and identify the existing communication

networks and explain their relationships with physical and human

features.

End unit assessment

1. “As it is difficult to reach all parts of the world; the photographs and

maps help to explore different physical and human features on the

earth.”

a. Identify physical features on topographic map of Rwanda.

b. Identify the human features on thematic maps of Rwanda.

2. Show different signs and symbols to be used in representing physical

and human features on maps/photography.

3. Discuss the relationships existing between settlement patterns and

physical features in your district and present them on a sketch map

using signs and symbols.

4. From the photographs taken at different places in Rwanda, prepare

a sketch map of captured physical and human features by using

conventional signs and symbols.