When should I use a flow map?

Showing migration, trade, or transport routes on a map ● Visualizing origin-destination patterns geographically

When should I avoid a flow map?

When geography is irrelevant to the flow story ● When there are too many routes creating spaghetti on the map

What are common mistakes with flow maps?

Not varying line width to encode flow volume ● Cluttering the map with too many overlapping routes

What data does a flow map need?

Minimum 3 rows, 5 columns (string, number, number, number, number). Expected columns: origin_lat, origin_lon, dest_lat, dest_lon, value. Named-location strings (e.g., 'New York') are geocoded automatically when coordinates are absent.

Flow

Flow Map

Overlays directional flow lines on a geographic map, showing movement of goods, people, or information between locations.

Global Airline Routes

Passenger volume between major hubs

View data (8 rows)

Chart data table: Global Airline Routes
value	source	target
450	New York	London
280	New York	Tokyo
320	London	Dubai
190	London	Singapore
210	Tokyo	Singapore
260	Dubai	Mumbai
170	Singapore	Sydney
140	Tokyo	Sydney

Make a flow map with your data

Use a flow map when…

Showing migration, trade, or transport routes on a map
Visualizing origin-destination patterns geographically

Avoid when…

When geography is irrelevant to the flow story
When there are too many routes creating spaghetti on the map

Data it needs

Property	Value
Min Rows	3
Min Columns	5
Column Types	stringnumbernumbernumbernumber
Notes	Expected columns: origin_lat, origin_lon, dest_lat, dest_lon, value. Named-location strings (e.g., 'New York') are geocoded automatically when coordinates are absent.

Visual anatomy

Marks

curved linepoint

Channels

line width (volume)position (geography)color (flow type)

Axes

Guiding principles

Consider instead

Sankey Diagram

When geography is not important

Connection Map

When showing presence of connections without volume

Common mistakes

Not varying line width to encode flow volume
Cluttering the map with too many overlapping routes

History

Charles Minard's 1869 map of Napoleon's Russian campaign is the most famous early flow map.

Accessibility notes

Render an origin-destination table beneath the map (origin, destination, volume) as the primary text alternative — geographic flow lines are inaccessible without it.

Got data? Let's see what works.

Drop your CSV. You'll get a Flow Map plus four alternatives - ranked by which one actually fits your data best.

Try it free