Spinning the Data? Thinking Critically about Maps

This problem-based learning activity introduces students to choropleth mapping while encouraging them to question the common assumption that maps are objective. Students explore how mapmakers’ choices can guide readers toward particular conclusions.

Students work through a case study in which they take on the role of a summer intern at an environmental organization. Using data on greenhouse gas emissions in Canada, they are asked to create a map the organization could use to support a funding request for climate change mitigation projects.

The case study challenges students to produce two different maps. In the first, they use the tertile approach to organise the data; in the second, they use the equal-size interval approach. They then decide which map is more effective for the grant application and justify their choice.

This activity is designed as an introduction to mapping at the beginning of the semester, before students start using GIS.

Tips:

• Before the activity begins, spend a few minutes discussing colour choices in maps. Show students two examples: a categorical colour scheme and a light‑to‑dark colour ramp. Ask them which scheme would be more appropriate for showing provinces with low, medium, and high greenhouse gas emissions, and why.
• This activity is easy to adapt to other topics that may be more engaging for students or better aligned with the course (e.g., physical activity levels, mental health, income inequality). To adapt it, simply replace the greenhouse gas emissions data with data on another topic.
• In addition this activity can be adapted to focus on other mapping decisions: for example, using global data and asking students to choose a map projection (such as Mercator, polar, or equal-area) that best supports their argument.

Topics: Mapping, Climate Action

Check out the workflow below to review the activity sequence.

By the end of this activity, students will be able to:

• Explain what a choropleth map is and what it’s used for
• Create choropleth maps using different data classification methods (tertiles and equal-size intervals)
• Explain, using examples, why maps are not objective sources of information and how they can be used to influence how people think
• Justify the choice of one map over another based on its effectiveness for a specific audience and purpose”