Selected city (size = population)
Other city — click to add
Predicted interaction (width)
Some cities lie outside the map window and are drawn at its edge.
Worked equation
All city pairs
Numbers match the badges on the map. Click a row to see its equation; bars show each pair relative to the strongest.
| # | Pair | Pop. A | Pop. B | Distance | Interaction | Relative |
|---|
Hover a settlement to inspect its market area.
Market areas served
Reading the diagram
Christaller assumed a flat, featureless plain with even population, equal transport in every direction, and rational consumers who travel to the nearest place selling what they need. Circles would leave gaps or overlap, so market areas become hexagons — the shape that packs perfectly with the least distance to the center.
- Threshold
- The minimum number of customers needed for a good or service to stay in business.
- Range
- The maximum distance people will travel to buy that good or service.
- Order
- Higher-order goods (surgeons, stadiums) have large thresholds and ranges, so only a few large centers offer them; low-order goods (bread, gas) appear everywhere.