S6 UNIT 2
Overview
Key Unit Competence: By the end of this unit, Learners should be able to interpret photographs, video images and draw sketches by reduction or enlargement of the photographs.
INTERPRETATION OF PHOTOGRAPHS AND VIDEO IMAGES
2.1. Definition and types of photographs
2.1.1. Definition
A photograph is a picture of an object or environment taken by a camera at a particular time in a given place.
some parts of the object or environment are seen while others may not be seen clearly. A hidden ground/area which cannot be seen by a camera when a photograph is taken is called a dead ground.
2.1.2. Major types of photographs
There are basically two types of photographs:
Ground photographs: These are photographs taken from the ground level
x-stics
- They record exactly what a person would see if he / she was standing on the ground level.
- It gives a horizontal view
- It gives great details of the landscape
- It covers a small area.
There are two categories of ground photographs:
a) Ground horizontal photographs: This is a photograph taken when a camera is held horizontally to the ground.
b) Ground oblique photographs: This is a photograph taken when the camera is titled at an angle facing the ground.
2. Aerial photographs:
These are photographs taken from aerial station using aircrafts, satellites, and other flying objects.
x-stics
- They cover a wide area
- Features are greatly reduced
- Show the top of the object
- They do not show the horizon
- They are more difficult to analyse.
There are two categories of aerial photographs:
a) Vertical aerial photographs: These are photographs taken when the camera is directly above (overhead) the objects or when it is perpendicular to the ground.
b) Oblique aerial photographs: These are photographs taken when the camera is titled at an angle below 90 degrees.
2.2. Sections of a photograph and interpretation of physical and human aspects
2.2.1. Sections of a photograph
- The foreground: It is the part of the photograph located nearest to the camera.
- The middle ground: It is the central part of the photograph.
- The back ground: It is the farthest part of the photograph that includes the horizon.
From vertical perspective, photographs are also divided in three parts: left, centre and right
Categories of photographs depending on the position of photography
Left background | Centre background | Right background |
Left middle ground | Centre middle ground | Right middle ground |
Left foreground | Centre foreground | Right foreground |
2.2.2. Interpretation of physical and human aspects on photographs and video images
a. Interpretation of physical aspects
- Climate: Climate in a photograph is indicated by rainfall and temperature. Heavy rainfall can be observed by presence of dense forests and crops like sugar cane, rice and tea while high temperature may be observed by the presence of poor vegetation, people wearing light clothes etc.
- Relief: The features of the relief depicted on a photograph include mountains, hills, valleys, escarpments, plateaus and plains. A hilly or mountainous landscape is indicated by the presence of steep slopes, presence of terraces, snow and glaciers on the top. Plateaus and plains are identified by a uniformly flat land with sloping edges and pools of water or irrigated land. Wide valleys with meanders and flood plains also suggest the presence of plain land.
Relief on vertical aerial photographs can be interpreted by observing the following:
- Flat areas can be identifiable by the presence of meandering rivers, straight roads and gentle bends.
- Plateaus can be indicated by presence of flat topped hills.
- Vegetation: This is the plant life that covers the earth surface; it is both natural and artificial.
- Drainage: Drainage is shown by the presence of water bodies on a photograph, such as streams, rivers, lakes, swamps, seas, and oceans. Others are man-made water features like wells, ponds, valley dams and boreholes. In photographs, drainage is interpreted in the following ways:
- Rivers appear with meandering channels with swampy vegetation along them.
- Swamps appear with luxuriant vegetation dominated by papyrus reeds.
- Soils: The types of soils can be identified by observing the types of crops grown there because there are crops that grow well in specific types of soils, for example, tea and coffee grow well in fertile volcanic soils. Where erosion took place, the soils are exposed.
b. Interpretation of human aspects
Photographs and video images can be very useful in the interpretation of human activities such as:
- Forestry: A forest is evidenced by the presence of both artificial and natural forests.
- Agriculture: Agricultural activities can be observed by the presence of food crops and cash crops as well as animals like cattle both exotic and traditional breeds.
- Transport and communication: Both transport and communication networks are evidenced by presence of motor vehicles, bicycles, roads, ships, airports, and communication facilities such as telephone lines and masts.
- Mining: This is shown by Open pits, people undertaking mining or a mineral processing plant show that there is mining taking place in that area.
- Industry: Industrialization is shown by the presence of industries emitting smoke from huge chimneys.
- Trade or commerce: the commerce is evidenced by trading centers with congested buildings and at times presence of markets.
- Settlement: It is evidenced by the presence of houses in different patterns.
2.3. Drawing sketches of photographs by reduction or enlargement
A sketch of a photograph focuses on the identification, marking using symbols and labeling marked features in their relative positions.
To draw a sketch of a photograph by enlargement or reduction requires the following steps:
- Draw a rectangle and a square of the size as requested on a piece of paper.
- Draw horizontal lines across the photograph by using a pencil to subdivide it into three equal sections. These will be the foreground, middle ground and background either reduced or enlarged as instructed.
- Draw vertical lines across the photograph by using a pencil. These will be left, centre and right.
- Place the framework of a photograph onto the prepared rectangle or square. The framework could be the guider in placing the various features in their respective positions.
- Enlarge or reduce the size of features and the frame as requested.
- When filling in the main features, it is better to start with the background or right by drawing the skyline as it appears on the photograph.
- It is better to place and label all important features either physical or human as they appear on the photograph, reduce or enlarge them as required.
Choose a suitable title, key, orientation of a sketch. It is possible to put on a sketch other elements of a sketch map which are useful in reading and interpreting it.
Therefore, a sketch of a photograph can be enlarged or reduced as shown below:
2.4. Relationship between physical and human aspects on photographs and video images
- Relief and transport: Transport routes occur on gentle slopes and avoid steep slopes and valleys since it is very expensive to construct roads in hilly areas.
- Relief and agriculture: On steep slopes, less agriculture takes place while on gentle slopes most agricultural practices are observed. The low lands are usually reserved for growing of vegetables, sugar cane, rice, and other crops that need enough water.
- Relief and settlement: Steep slopes tend to discourage construction of houses while gentle slope encourage population settlement.
- Drainage patterns and settlement: Settlement occurs in well drained areas and avoids lake shores or river banks because of floods and associated problems.
- Drainage and transport: Transport routes are usually found in well drained areas. For example, roads cannot be constructed in swampy areas due to excessive water. Water transport occurs on water bodies like rivers, lakes,