4.1 Geographical skills: Interpret maps, photographs, satellite images and graphs.

4. Geographical Skills and Investigations

4.1 Interpret Maps, Photographs, Satellite Images and Graphs 📍📸🛰️📊

🔍 Exam Tip: When you see a question about a map, photograph, satellite image or graph, start by identifying the type of data and the key information requested (e.g., location, trend, scale).

Interpreting Maps

Think of a map as a recipe card for a journey. It tells you where you are, what you will see, and how far things are.

• Scale – the ratio between map distance and real distance. Example: 1 cm on the map = 10 km in reality.
• Legend – the key that explains symbols.
• Compass rose – indicates directions.
• Contours – lines of equal elevation; the closer they are, the steeper the slope.

To calculate real distance from a map:

1. Measure distance on the map (e.g., 3 cm).
2. Multiply by the scale factor (e.g., 10 km/cm).
3. Result: $3\,\text{cm} \times 10\,\text{km/cm} = 30\,\text{km}$.

📌 Exam Tip: Always check the scale and use the ruler to measure distances accurately.

Interpreting Photographs 📸

Photographs are like snapshots of time. They capture a moment but you must read the context and details to understand the bigger picture.

• Perspective – front, side, aerial. Aerial photos give a bird’s‑eye view, similar to satellite images.
• Scale – can be inferred from known objects (e.g., a car is ~4 m long).
• Colour – indicates vegetation health (green = healthy, yellow = stressed).
• Human activity – roads, buildings, deforestation signs.

🔎 Exam Tip: Look for patterns such as straight lines (roads) or irregular shapes (water bodies) and relate them to map features.

Interpreting Satellite Images 🛰️

Satellite images are like global cameras that capture the Earth from space. They provide large‑scale views and can show changes over time.

• Multispectral bands – different colours represent different wavelengths (visible, infrared).
• NDVI (Normalized Difference Vegetation Index) – calculated as $NDVI = \frac{NIR - RED}{NIR + RED}$. Values close to +1 mean lush vegetation.
• Temporal changes – compare images from different dates to spot deforestation, urban growth, or flood extent.

??? Exam Tip: When asked to compare two satellite images, note the date, colour changes, and any new features.

Interpreting Graphs 📊

Graphs are like charts of stories. They turn raw data into visual patterns.

• Bar charts – compare categories.
• Line graphs – show trends over time.
• Pie charts – illustrate proportions.
• Scatter plots – reveal relationships between two variables.

Key steps to analyse a graph:

1. Read the title and axis labels.
2. Identify the scale and units.
3. Note any key points or trends.
4. Answer the question based on the evidence.

⚠️ Exam Tip: Always check the axis units (e.g., km, people, %). Misreading units can lead to wrong conclusions.

🎓 Final Exam Strategy:

• Read the question carefully – what is being asked?
• Identify the data source (map, photo, satellite, graph).
• Use the steps above to extract the required information.
• Answer in your own words, citing evidence from the visual.