Connection Map
A map showing connections between locations as lines or arcs — without encoding flow volume. It reveals the existence and pattern of relationships across geographic space.
// 01 — The chart
What it looks like
A connection map showing airline routes radiating from a hub airport. Each arc represents a direct connection — line thickness is uniform since volume is not encoded.
// 02 — Definition
What is a connection map?
A connection map (also called a link map or arc map) draws lines between points on a map to show that a relationship exists between those locations. Unlike a flow map, which encodes the volume of movement through line width, a connection map treats all links as equal — the focus is purely on the structure of the network.
Connection maps are one of the simplest geospatial visualizations to build and read. You place your locations as dots, then draw a line (straight or curved) between every pair that has a relationship. The result is a web of connections that reveals hub-and-spoke patterns, geographic clustering, and the overall reach of a network.
The key design choice is whether to use straight lines or curved arcs. Arcs (great-circle curves) are preferred when many connections cross the same area, because they create visual separation between overlapping routes. Straight lines work fine for sparse networks with few crossings.
Classic example: The most familiar connection map is an airline route map found in the back of in-flight magazines. A hub airport sits at the center with arcs fanning out to every destination, instantly showing the airline’s network reach.
// 03 — Anatomy
Parts of a connection map
// 04 — Usage
When to use it — and when not to
- You want to show that relationships exist between geographic locations
- Your network has a clear hub-and-spoke structure worth revealing
- You need a simple overview of which places are linked
- Visualizing airline routes, shipping lanes, or communication links
- Comparing network reach between two hubs or time periods
- Your audience needs an intuitive sense of geographic connectivity
- You need to encode the volume or magnitude of flow — use a flow map instead
- Too many connections create an unreadable hairball of lines
- Connections are not geographic — use a network graph or chord diagram
- You want to show movement direction — add arrowheads or use a flow map
- Your data is about areas, not point-to-point links
- Precise route paths matter — connection maps show links, not actual paths
// 05 — Reading guide
How to read a connection map
Follow these steps whenever you encounter a connection map.
Identify the nodes and what they represent
Each dot on the map is a location — a city, airport, warehouse, or data center. Read the labels to understand what’s being connected.
Look for hubs
Nodes with many connections radiating outward are hubs. They’re the most connected locations in the network and often the most important operationally.
Trace the geographic pattern
Do connections span long distances or cluster regionally? Are there cross-continental links, or is the network contained within a small area?
Check for isolated nodes
Locations with zero or very few connections may represent underserved areas or recent additions to the network. Their absence of lines is meaningful.
Note what is NOT shown
Connection maps show existence of links, not their volume, speed, or cost. Two arcs that look identical may carry vastly different amounts of traffic.
// 06 — Pitfalls
Common mistakes
×Too many connections creating a hairball
Fix: Filter to the top-N connections, use bundling to merge overlapping arcs, or let users interactively highlight one hub at a time.
×Implying volume when none is encoded
Fix: Keep all lines the same width. If you need to show traffic volume, switch to a flow map with proportional line widths.
×Using straight lines when arcs cross heavily
Fix: Curved arcs (great-circle paths) separate overlapping connections visually. Straight lines pile up and become unreadable in dense networks.
×Missing geographic context
Fix: Without a basemap or at least country outlines, nodes are just dots in space. Always include enough geographic reference for the audience to orient themselves.
×No labels on endpoints
Fix: Unlabeled dots are useless. At minimum, label the key hubs. Use hover tooltips or a legend for secondary nodes to avoid clutter.
// 07 — In the wild
Real-world examples
Airline route maps
Every major airline publishes a connection map in its in-flight magazine. Hub airports sit at the center with arcs fanning out to dozens of destinations, instantly communicating network reach and coverage.
Submarine cable maps
TeleGeography’s submarine cable map is one of the most iconic connection maps ever made. It shows every undersea fiber optic cable connecting continents, revealing the physical infrastructure of the internet.
Facebook friendship connections
Paul Butler’s famous 2010 visualization plotted Facebook friendships as faint blue arcs on a dark background. The density of connections literally drew a map of the world — no basemap needed.
// 08 — Quick reference
Key facts
// 09 — Variations
Types of connection maps
Connection maps come in several styles depending on the line shape and network structure.
Straight-line connection map
Connects points with direct straight lines. Simple and clean for sparse networks with few crossing links.
Great-circle arc map
Uses curved arcs that approximate the shortest path over the globe. Reduces visual clutter for dense or long-distance networks.
Hub-and-spoke map
All connections radiate from a single central hub. Classic layout for airline routes, logistics depots, or broadcast networks.
Mesh / peer-to-peer map
Multiple nodes connect to many others with no single hub. Reveals the decentralized structure of peer networks.
// 10 — FAQs
Frequently asked questions
What is a connection map?+
A connection map (also called a link map or arc map) draws lines between points on a map to show that a relationship exists between those locations. Unlike a flow map, which encodes the volume of movement through line width, a connection map treats all links as equal — the focus is purely on the structure of the network.
When should you use a connection map?+
Use a connection map when you want to show that relationships exist between geographic locations. It also works well when your network has a clear hub-and-spoke structure worth revealing, and when you need a simple overview of which places are linked.
When should you avoid a connection map?+
Avoid a connection map when you need to encode the volume or magnitude of flow — use a flow map instead. It is also a poor fit when too many connections create an unreadable hairball of lines, or when connections are not geographic — use a network graph or chord diagram.
Is a connection map suitable for dashboards?+
Yes — a connection map can work well in dashboards as long as the panel is large enough for readers to perceive the encoded values, has a clear title, and includes the legend or axis labels needed to interpret it.
What category of chart is a connection map?+
Connection Map belongs to the Geospatial family of charts. Charts in that family are designed to answer the same kind of question, so they often work as alternatives when one doesn't quite fit your data.
How do you read a connection map?+
Start with the axis labels and legend, then look at the overall shape before zooming into individual marks. Compare prominent features against the rest of the data, and verify any conclusion against the underlying numbers when precision matters.