Knowledge Organiser: Presenting Geographical Data
Key Techniques
- Bar chart — discrete categories, comparison
- Line graph — continuous data over time/distance
- Scatter graph — relationship between two continuous variables
- Choropleth — relative values across areas (spatial)
- Dispersion diagram — spread of data at each site
- Kite diagram — abundance along a transect
- Flow map / desire lines — direction and volume of movement
- Pie / proportional circle — proportions of a total
- Radar / spider diagram — multi-variable EQS comparison
Key Terms
- Choropleth — shading shows relative values per area
- Isoline — connects equal values on a map
- Desire line — straight line showing movement direction + volume
- Dispersion diagram — plots all values to show spread
- Kite diagram — transect abundance, symmetrical around centre
- Line of best fit — trend line through scatter graph points
- Spearman's rs — numerical measure of correlation strength (−1 to +1)
- Proportional circle — circle area ∝ value
Decision Rules
- Two continuous variables + relationship test → Scatter graph
- Discrete categories + comparison → Bar chart
- Continuous over time/distance → Line graph
- Spatial distribution across areas → Choropleth
- Proportions of a total → Pie / proportional circle
- Spread of data at sites → Dispersion diagram
- Species along transect → Kite diagram
- Movement direction + volume → Flow map
- Multi-variable site comparison → Radar diagram
Must-Know Analysis Phrases
- "This suggests..." (interpretation)
- "This is consistent with..." (theory link)
- "This could be because..." (causal explanation)
- "An anomaly at [X] may reflect..." (outlier explanation)
- "The data shows a strong negative correlation (rs = X)..." (statistical evidence)
- "A limitation of this technique is..." (evaluation)
- "This is more appropriate than [alternative] because..." (justification)
- Always include specific values in brackets: "(52 vs 156 vehicles/hour)"
Common Mistakes
- Choosing the wrong graph type: Scatter graphs show relationships between two continuous variables; bar charts compare discrete categories; line graphs show change over continuous time or distance — always match the graph type to the data type and the hypothesis
- Drawing a choropleth without a key: A choropleth map requires a colour/shading key with clear class boundaries — without it, the map cannot be read and will score zero for presentation technique questions
- Interpreting Spearman's rs without checking significance: An rs value of 0.6 sounds strong, but if it does not exceed the critical value at 95% confidence for your sample size, the correlation is NOT statistically significant — always compare to the critical value table
- Listing data values instead of analysing patterns: Describing every data point ("Site 1 had 52, Site 2 had 61...") scores Level 1 — use TACT (Trend, Anomaly, Comparison, Terminology with specific figures) to reach Level 2 and above
Memory Aid
When you face an exam question asking you to choose or justify a presentation technique, run through DECIDE: D — Data typeWhat kind of data do you have? Continuous (measured values on a scale), discrete (counted categories), ordinal (ranked), or locational (tied to specific places)? E — Examine the research questionWhat are you trying to show? A trend over time? A spatial distribution? A relationship between two variables? A comparison of categories? Different questions need different techniques. C — Consider scaleHow many data points do you have, and where were they collected? Twelve paired measurements suit a scatter graph. Data from a transect at 50 cm intervals suits a kite diagram. Data collected across administrative zones suits a choropleth. I — Identify the relationshipWhat pattern are you trying to communicate? Correlation between two variables? Proportions of a total? Relative values across a map? The pattern you want to show determines the technique that will show it most clearly. D — Draw accuratelyWhatever technique you choose, draw it correctly: labelled axes with units, consistent scale, title, legend where needed, north arrow and scale bar on maps. Technical accuracy earns marks even if the analysis is weak. E — Explain your choiceThis is the mark-earning step. State why your chosen technique suits your data type and research question. Mention at least one alternative technique and explain why it would be less appropriate. This is what separates Level 2 from Level 3 answers. DECIDE: Data type → Examine the question → Consider scale → Identify the relationship → Draw accurately → Explain your choice.