What’s the story?

Study the map briefly. On first impression, which of the following offers the best evaluation of this map? Click on the button that provides the best assessment.

Projected impact of climate change on agricultural yields
Image by @Enescot / CC BY 2.5
Are you sure about this? At a glance, it's hard to tell whether Africa or South Asia are most vulnerable to climate change. It feels like we have to work quite hard to interpret this map, doesn't it?
This is a fair assessment. The use of different shades of green to show 'winners' works quite well. But the multiple colours used to show 'losers' is hard to interpret. There are a lot of categories too, perhaps more than are needed.
Are you sure about this? It seems a rather harsh assessment. It's fairly easy to work out who the main 'winners' are (green shading), isn't it?

Thinking critically about presentation

Read the statements below. Select the appropriate smiley to answer the following question:

Assess the strengths and weaknesses of the way data are presented in Figure 1. [AO3, 5 marks]

Projected impact of climate change on agricultural yields
Image by @Enescot / CC BY 2.5

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QuestionCwestiwn Your AnswerEich ateb

Suggested response

Strong agricultural growth is predicted in the northern hemisphere and the weakest growth in the global south.

Response: Although this is an AO3 (analytical) response, the focus is a description of the data rather than an assessment of the presentation method.

The most important reason for weaker growth could be a drier climate.

Response: This is an AO2-style causal response which tries to explain the pattern instead of offering an assessment of the map’s quality.

Shades of light and dark green are an effective way of communicating positive changes.

Response: This is an AO3 response correctly focused on the strengths and weaknesses of the map. Using gradations of a single colour is best practice.

Mixed shades of dark orange, light orange and red do not communicate negative changes in an easy-to-understand way.

Response: This is an AO3 response correctly focused on the strengths and weaknesses of the map. Can you suggest an alternative way of shading this map, which would communicate change more effectively?

The map's nine categories make patterns harder to interpret - six or seven categories might have worked better.

Response: This is an AO3 response correctly focused on the strengths and weaknesses of the map. Because ten data classes have been used, the pattern is harder to analyse than it needs to be. 6 or 7 classes might suffice if the objective (or ‘story’) of the map is to reveal broad global variations in future carbon cycle ‘winners and losers’.

The map only shows changes at the national level - it would be better to break up big countries like Russia to show regional variations.

Response: This is an AO3 response correctly focused on the strengths and weaknesses of the map. It is always worth thinking critically about a map’s scale or level of detail.

The most important reason for stronger growth in the northern hemisphere could be warmer temperatures.

Response: This is an AO2-style causal response which tries to explain the pattern instead of offering an assessment of the map’s quality.

There are two anomalies in Central Africa where positive growth is shown in a region where other countries have declining productivity.

Response: Although this is an AO3 (analytical) response, the focus is a description of the data rather than an assessment of the presentation method.

Increased productivity in some countries may be due to warmer temperatures for cold mountainous regions.

Response: This is an AO2-style causal response which tries to explain the pattern instead of offering an assessment of the map’s quality.

Extension activity

Find other choropleth maps in your course textbook or using an online image search. Look for evidence of good practice and poor practice in the way they have been created. In addition to the number of classes included, think too about how colour is used in different maps. Some unprofessional choropleth maps use too many wildly varying colours which makes it harder to grasp immediately the pattern of 'highs and lows' (which are best shown with a gradation from darker to lighter colours).