Welcome to Graphical Skills!
In Geography, we don't just look at maps and photos; we look at data. Data is just a fancy word for information. To make sense of all this information—like how much it rains or how many people live in a city—geographers use graphs and charts. Think of a graph as a picture of numbers. It’s much easier to see a pattern in a picture than in a long list of boring digits!
In this guide, we will learn how to choose the right graph, how to draw them perfectly, and how to "read" what they are telling us. Don't worry if you find math or charts a bit scary; we’ll take it one step at a time.
1. Choosing and Drawing the Right Graph
Not every graph works for every type of data. If you use the wrong one, your "picture" won't make sense. Here are the main types you need to know for your AQA exam:
Line Charts
What they are: A series of points joined by a line.
Best for: Showing changes over time (continuous data).
Example: How the temperature in London changes from January to December.
Top Tip: Always use a ruler to join your dots!
Bar Charts and Histograms
Bar Charts: Use separate bars to compare different categories.
Example: Comparing the amount of recycled waste in five different cities.
Histograms: These look like bar charts but the bars touch each other. They show "frequency" (how often something happens) within groups or intervals.
Example: Showing how many pebbles in a river fall into different size groups (e.g., 0-5cm, 6-10cm).
Common Mistake: Forgetting to leave gaps between bars on a standard bar chart! Only histograms have touching bars.
Pie Charts and Divided Bar Charts
What they are: These show how a "whole" thing is split into parts.
Analogy: Think of a Pie Chart as a real pizza. The bigger the slice, the more people chose that topping. A Divided Bar Chart is like a long Subway sandwich cut into different sized portions.
Example: Showing the percentage of energy coming from coal, gas, and wind.
Scattergraphs
What they are: Dots plotted on a graph to see if there is a relationship (correlation) between two things.
Example: Does the amount of rainfall increase as you go higher up a mountain?
Key Term: Line of Best Fit. This is a straight line drawn through the middle of the dots to show the general trend. If the dots go up together, it's a positive correlation. If one goes up while the other goes down, it's a negative correlation.
Population Pyramids
What they are: Two back-to-back bar charts showing the number of males and females in different age groups.
What to look for: A wide base means many babies are being born. A narrow top means a lower life expectancy.
Did you know? A pyramid that looks like a "beehive" usually belongs to a wealthy country (HIC) where people live a long time!
Quick Review: The "TALKS" Mnemonic
Whenever you draw a graph, check your TALKS:
• Title (What is it about?)
• Axes (Are they drawn with a ruler?)
• Labels (What do the axes represent?)
• Key (If you used colors or symbols, what do they mean?)
• Scale (Are the numbers going up in equal steps, like 2, 4, 6...?)
2. Geographical Maps and Diagrams
Sometimes geographers combine graphs with maps. These can look complicated, but they follow simple rules.
Choropleth Maps
What they are: Maps where areas are shaded in different colors or patterns to show values.
Rule: Usually, the darker the color, the higher the value.
Example: A map of the UK where dark green areas have lots of forests and light green areas have very few.
Isoline Maps
What they are: Maps with lines that join up places with the same value.
Example: Contour lines on a map show height. Isotherms show equal temperature.
Understanding Gradient: If the lines are very close together, the change is steep (like a steep hill). If they are far apart, the change is gentle (flat land).
Dot Maps and Proportional Symbols
Dot Maps: Each dot represents a specific amount (e.g., 1 dot = 100 cows). Where the dots are thickest, the density is highest.
Proportional Symbols: These use symbols (usually circles) of different sizes. A big circle means a big number. For example, a map of cities where the circle size shows the population.
Flow Lines and Desire Lines
What they are: Arrows that show movement between places.
The Secret: The thickness of the arrow shows how much is moving. A thick arrow might mean 1,000 migrants, while a thin line means 10.
Difference: Flow lines follow the actual route (like a road). Desire lines are straight lines from point A to point B to show the general direction of travel.
Key Takeaway: Maps with symbols or shading help us see spatial patterns—where things are happening and where they aren't.
3. Interpreting Data (Analysis)
In your exam, you will often be asked to "Describe the pattern" or "Interpret the graph." Follow these three steps to get full marks:
Step 1: The General Trend
What is the "big picture"? Is the line going up? Is the shading mostly in the north? Use words like increase, decrease, steady, or fluctuate (goes up and down).
Step 2: Use Evidence (The Data)
Never just say "it went up." Say "It increased from \(10mm\) in January to \(50mm\) in July." Always include units!
Step 3: Anomalies
Look for the "weird" bits. Is there one dot on the scattergraph that is far away from the others? Mention it! Geographers love to spot things that don't fit the rule.
Dispersion Graphs
What they are: A vertical line where dots are plotted to show the "spread" of data.
Analogy: Imagine everyone in your class lines up by height. If everyone is roughly the same height, the dots are bunched together. If there are very tall and very short people, the dots are dispersed (spread out).
Why use them? To see the range and if there are clusters of data points.
4. Common Mistakes to Avoid
• Inaccurate Plotting: Use a sharp pencil. If a point is supposed to be at 15, don't put it at 17!
• Missing the Key: If you use three colors for a pie chart but don't explain what they mean, the examiner can't give you points.
• Confusing X and Y axes: Remember: X is across (the horizontal line). Y is high (the vertical line).
• Reading the Scale Wrong: Check if the scale goes up in 1s, 2s, 5s, or 10s before you start reading the data.
Encouragement: Graphical skills are like riding a bike. It feels wobbly at first, and you might mix up your "Isolines" with your "Choropleths," but once you've practiced a few, you'll be able to do it without thinking! These skills are great because once you master them, they are "easy marks" in the exam.
Summary: Section Takeaways
• Line graphs = trends over time.
• Bar/Histograms = comparing amounts or frequencies.
• Scattergraphs = relationships (positive or negative).
• Choropleth = shading for density.
• Proportional symbols = size shows quantity.
• Isolines = lines of equal value (like contours).
• Always use "TEA" when describing: Trend, Evidence (numbers), and Anomalies.