Flow maps show movement from one place to another using arrows or lines. They help geographers see patterns in migration, trade, transportation, communication, and the spread of ideas or disease. The direction, thickness, and color of each arrow can turn a simple map into a clear picture of how places are connected.
This skill matters because many real world problems involve movement across space.
Key Facts
- Flow maps show movement between an origin and a destination.
- Arrow direction shows where the movement starts and where it goes.
- Line or arrow width often represents quantity, so wider arrows usually mean more people, goods, money, or information.
- A legend is needed to explain what each arrow width, color, or symbol represents.
- Total flow into a place = sum of all incoming flows.
- Net flow = total incoming flow - total outgoing flow.
Vocabulary
- Flow map
- A flow map is a map that uses arrows or lines to show movement between places.
- Origin
- An origin is the starting location of a movement shown on a flow map.
- Destination
- A destination is the ending location of a movement shown on a flow map.
- Legend
- A legend explains the meaning of symbols, colors, line widths, and other map features.
- Scale
- Scale describes the relationship between distance on the map and distance in the real world.
Common Mistakes to Avoid
- Reading every arrow as the same size, which is wrong because arrow width may represent different amounts of movement.
- Ignoring the arrowhead, which is wrong because direction is one of the main pieces of information on a flow map.
- Forgetting to check the legend, which is wrong because colors and line widths can mean different things on different maps.
- Treating curved arrows as exact travel routes, which is wrong because flow arrows often show general movement rather than the precise path taken.
Practice Questions
- 1 A flow map shows 800 students moving from Town A to City B, 300 from Town C to City B, and 200 from City B to Town D. What is the total incoming flow to City B?
- 2 A map legend says a 1 mm arrow represents 100 tons of wheat. If an arrow is 6 mm wide, how many tons of wheat does it represent?
- 3 A flow map shows thick arrows from rural areas to a large city and thin arrows leaving the city. Explain what this pattern might suggest about population movement and urban growth.