SME
Cartography · Problem type
Best thematic map for the data
Use this for “You have the median household income of every county in a state. Which kind of thematic map shows it best?”
Sort
Which kind of thematic map fits this data?
Tap a card, then tap its group.
Ask first what the data counts and where it lives: in areas, at points, everywhere, or between places.
Assumptions
•
Rates and percents tied to areas suit a choropleth; raw counts suit dots or sized symbols placed at the spot they count.
•
A quantity that exists everywhere, measured at points, becomes a smooth surface of isolines.
•
Movement between places, with an amount, is drawn as lines of varying width.
Topic check
See what you know: 5 questions on this topic
New questions each time. Pass to mark it complete.
Related lessons
Thematic mapping
Main lesson
Rates, not counts, on a choropleth
Use this for “County A has 340 cases among 85,000 people; county B has 900 among 450,000. Which county should be shaded darker on a choropleth?”
Proportional-symbol radius
Use this for “The largest city, 1,000,000 people, gets a 20 mm circle. How big a circle does a city of 250,000 get?”