IGCSE Geography 0460 - 4.1 Geographical Skills: Interpreting Maps, Photographs, Satellite Images and Graphs

This section outlines the skills required to interpret various geographical data sources, a crucial aspect of geographical investigation and analysis. We will explore how to extract meaningful information from maps, photographs, satellite images, and graphs.

1. Interpreting Maps

1.1 Types of Maps

Different types of maps display different kinds of information. Understanding these is key to accurate interpretation.

• Topographic Maps: Show physical features like elevation, rivers, and landforms.
• Political Maps: Display countries, states, capitals, and boundaries.
• Thematic Maps: Focus on a specific theme, such as population density, climate, or vegetation.
• Planning Maps: Used for urban planning, showing infrastructure, land use, and zoning.
• Contour Maps: A type of topographic map using lines to represent elevation.

1.2 Map Symbols and Legends

Maps use symbols (icons) and a legend to communicate information. The legend is essential for understanding what each symbol represents.

Common map symbols include:

• Roads: Different colours and thicknesses indicate different types of roads.
• Rivers: Blue lines represent rivers, with width indicating size.
• Forests: Green areas indicate forests.
• Buildings: Small squares or outlines represent buildings.
• Contour Lines: Lines connecting points of equal elevation. The closer the lines, the steeper the slope.

1.3 Scale

Map scale indicates the relationship between distances on the map and distances on the ground. There are three main types of scale:

• Verbal Scale: Uses words to express the scale (e.g., "1:50,000").
• Representative Fraction (RF): A ratio expressing the relationship (e.g., 1:50,000). The numerator represents the distance on the map, and the denominator represents the corresponding distance on the ground.
• Graphic Scale: A bar on the map representing a specific ground distance.

Example: A scale of 1:50,000 means that 1 cm on the map represents 50,000 cm (or 500 meters) on the ground.

1.4 Coordinates

Coordinates are used to pinpoint locations on a map. Two main systems are used:

• Grid References: Use letters and numbers to identify locations on a grid system (e.g., OSGB 36 grid).
• Decimal Latitudes and Longitudes: Use degrees, minutes, and seconds to specify locations on the Earth's surface.

2. Interpreting Photographs

2.1 Types of Photographs

Photographs provide visual information about a location. Different types offer varying perspectives.

• Aerial Photographs: Taken from an aircraft, providing a bird's-eye view.
• Satellite Photographs: Taken from orbiting satellites, offering a wider view of the Earth.
• Ground Photographs: Taken from the ground, providing a detailed view of a specific area.

2.2 Features to Identify

When interpreting photographs, look for:

• Landforms: Mountains, valleys, plains, coastlines.
• Vegetation: Types and distribution of plants.
• Human Settlement: Buildings, roads, infrastructure.
• Land Use: How land is being used (e.g., agriculture, industry, residential).
• Evidence of Human Activity: Pollution, deforestation, construction.

3. Interpreting Satellite Images

3.1 Types of Satellite Images

Satellite images are acquired using various sensors, providing different types of information.

• Optical Images: Capture visible light, similar to what the human eye sees.
• Infrared Images: Detect heat signatures, useful for identifying thermal differences.
• Radar Images: Use radio waves to penetrate clouds and darkness, providing information about surface features.

3.2 Using Satellite Images for Analysis

Satellite images are powerful tools for geographical analysis. They can be used to:

• Monitor changes over time: Compare images taken at different times to track deforestation, urban growth, or coastal erosion.
• Assess environmental conditions: Identify areas of drought, flooding, or pollution.
• Study land use patterns: Analyze how land is being used and how it is changing.

4. Interpreting Graphs

4.1 Types of Graphs

Graphs are used to represent data visually, making it easier to identify trends and patterns.

• Line Graphs: Show changes in data over time.
• Bar Charts: Compare data between different categories.
• Pie Charts: Show the proportion of different categories to a whole.
• Scatter Graphs: Show the relationship between two different variables.

4.2 Extracting Information from Graphs

To interpret graphs effectively:

• Identify the axes: Understand what each axis represents.
• Read the data: Determine the values represented by the points on the graph.
• Identify trends: Note any increases, decreases, or fluctuations in the data.
• Make comparisons: Compare different categories or time periods.
• Draw conclusions: Summarize the key findings of the graph.

Example: A line graph showing population change over time can reveal whether a population is growing, shrinking, or remaining stable.

5. Combining Different Data Sources

Often, geographical investigations require the interpretation of multiple data sources. This allows for a more comprehensive understanding of a location or phenomenon.

Example: Combining a satellite image showing deforestation with a graph showing rising global temperatures can help to understand the link between deforestation and climate change.