This tool covers four ways cartographers turn numbers into maps: choropleth, dot density, isoline, and proportional symbol maps. Every map uses real data, loaded live, so you'll need an internet connection.
1Getting started
Click any concept card below, or use the tab bar under it, to jump straight to a map type. You don't have to go in order.
2What's on each map screen
- Top controls — module-specific settings (see below).
- The map itself — pan by dragging, zoom with the + / − buttons or your scroll wheel. Hover shapes, dots, or symbols for details.
- Legend — bottom-left corner, explains what colours/sizes mean.
- How to read it — a box on the right with key rules for that map type.
- Check your reading — a 3-question quiz with instant feedback; wrong answers reveal the correct one.
3Module-by-module controls
| Choropleth | Variable dropdown (density / GDP) and Quantile / Equal interval toggle — watch the legend and colours change together. |
| Dot Density | Dot value slider — fewer people per dot = more dots = more detail (but busier). |
| Isoline | Preset buttons (Mt. Fuji, Alps, Rockies, Andes) jump to mountain ranges; pan/zoom freely — contour lines redraw live, give it a second after a big jump. |
| Proportional Symbol | Toggle Area ∝ Value (correct) vs Radius ∝ Value (common mistake) — compare the same cities in both modes. |
Tip: hover any shape, dot cluster, or circle to see the exact place name and value — useful for the quiz questions.
4If something looks wrong
- Blank/grey map area — real data is loading; wait ~15 seconds, then refresh if it's still blank (needs internet).
- Isoline map looks blocky or slow — normal, contours are calculated live from real elevation data each time you pan or zoom.
- Want to start over — just refresh the page; nothing is saved.
Data: World Bank Open Data (population & GDP, 2022) · Natural Earth (boundaries) · AWS Open Data Terrain Tiles (elevation) · UN World Urbanization Prospects (city population).
