BTA Charts
ChartsFlow & Relationship

Round Sankey

A circular variant of the classic Sankey diagram. Categories sit on the rim as arcs, and ribbons inside the circle represent directed flows from source to target. Ideal for trade flows, migration patterns, inter-team communication, or any "from X to Y" dataset where you want to see both incoming and outgoing volume at a glance.

Examples

When to Use

  • Showing directed flows between a moderate number of categories (3–12)
  • Comparing the relative volume of inbound vs. outbound activity per node
  • Trade or migration analysis between regions
  • API call patterns between microservices
  • Inter-department or inter-team collaboration mapping

Data Roles

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Build These Examples

Source, Target, and Values are all you need for a single diagram — add the optional Group well to break the canvas into small-multiple panels.

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Settings

Layout

Arc Thickness

number

Arc thickness as percentage of outer radius (1–20).

Default: 8

Pad Angle

number

Padding between arcs in degrees (0–8).

Default: 2

Top N

number

Limit to top N arcs by total flow; 0 = unlimited (long tail collapses into an Others arc).

Default: 0

Sort

dropdown

Node ordering: total desc/asc, alphabetical, or fixed insertion order.

Default: totalDesc

Ribbons

Direction

dropdown

Show arrowheads on ribbons (directed) or render them as undirected bands.

Default: directed

Color Mode

dropdown

Per-ribbon palette gradient, custom min→max, source-end, target-end, magnitude, or solid.

Default: gradient

Default Opacity

number

Base ribbon opacity (0–1).

Default: 0.55

Labels

Show Labels

boolean

Display category labels around the arc.

Default: true

Label Mode

dropdown

Curved labels along the arc, or horizontal text.

Default: alongArc

Min Arc Angle

number

Hide labels for arcs smaller than this angle in degrees.

Default: 2

Common settings like Tooltip, Small Multiples, and Color Scheme are covered in Shared Concepts.

Tips & Best Practices

  • Round sankey works best with fewer than 12 nodes — Top-N collapses the long tail into an "Others" arc when you exceed that
  • Hover over an arc or ribbon to focus its connections; click to pin the focus state
  • Use a sequential palette like "blues" or "teals" for ordinal categories, "vibrant" for distinct ones

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