Bubble Chord Diagram Generator - Circular Collaboration Network

Free online bubble chord diagram generator. Upload a two-section CSV — source,target,value links first, then a blank line and name,size,color node metrics — to render the same style of diagram used in bibliometric collaboration networks: a ring of bubbles whose size encodes node scale, whose aqua-to-blue fill encodes strength, joined by center-bowed chords whose thickness encodes link strength. Export HD PNG / SVG, no watermark. The page ships with sample data of 24 countries and 46 collaborations so you see the result immediately.

What is a bubble chord diagram

A bubble chord diagram is the visual upgrade of the classic chord chart: instead of encoding each node’s own value with the length of an arc segment, it turns every node into a bubble on the circle — the bubble diameter carries the first metric, its fill walks a continuous aqua-to-blue colormap for the second, and the chords only need to say how strong each pair is. Because the ring itself carries no encoding, labels still fit comfortably around the outside even with ~30 nodes. This is the look made famous by scientific collaboration-network plots.

What you can do

• Two-section CSV — first source,target,value links (up to 120 rows), then name,size,color node metrics (optional).
• Double encoding — bubble radius scales with the square root of size; color normalizes color across a 5-stop aqua-to-blue colormap.
• Center-bowed chords — every link leaves its two bubble edges and bows toward the center, width proportional to value, overlaps darkening naturally.
• Radiating labels — node names fan along the radius outside the ring, flipped on the left half to stay readable.
• Light / dark — one-click canvas switch; exports match the preview.
• PNG / SVG export — PNG at 2x resolution, SVG as true vector, both watermark-free; everything stays in your browser.

How to use

1. The sample 24-country network renders on load; upload or drag your own CSV (or click “Load sample”) to replace it.
2. Toggle light / dark mode when you like.
3. Click “Download PNG” or “Download SVG” to save the figure.

CSV template (two sections separated by one blank line; keep text pure ASCII to avoid Excel mojibake):

source,target,value
USA,China,210
USA,Germany,180
USA,France,120
Germany,France,95
Japan,China,92

name,size,color
USA,750,42.0
China,700,39.0
France,380,41.0
Japan,300,40.0

Where it fits

• Research collaboration — country / institution co-authorship flows plus each node’s output and impact.
• Supply chain & business — partner or channel cooperation amounts plus each end’s scale and rating.
• Teams & organizations — cross-department traffic plus headcount and activity.
• International relations — trade or migration between countries plus economy size and per-capita level.
• Open-source ecosystems — dependency strength between projects plus stars and contributor activity.

Notes

Supports .csv text files; duplicate links accumulate, self-loops are ignored, and nodes missing from the metric section fall back to their total flow. From 2 up to 40 nodes. PNG exports at 2x resolution, SVG as a freely scalable vector.

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Last verified: 2026-09-03

How to read this chart

Follow three channels: ① whose bubble is largest = largest scale (the concentric-circle legend top-right marks 1/3, 2/3 and full value); ② whose fill is deepest = highest strength (the gradient bar ends match your data min and max); ③ which chord is thickest = strongest pair. Note bubble color encodes the node’s own second metric while chord thickness encodes relationship strength — a big, pale bubble can mean “lots of volume, average quality”.