SANKEY

column-stacked nodes joined by width-true bands. Needs: 2-3 node columns + links between adjacent columns; conserved totals.

flowcompositionvariance-decomposition

DL-01 AGRAW

Use when

where things came from and where they went, conserved end to end
sources to routes to destinations in one figure

Do not use when

cyclic flows (sankeys are acyclic by construction)
more than ~6 nodes per column

See instead

one quantity bridges start to end: CH-FLO-01
no movement between states: CH-PTW-01

Alternatives

CH-FLO-01 (one total changing through steps)
CH-PTW-01 (composition without flow)

Rules

band width IS the value, at both ends; totals conserve per node
nodes stacked deterministically in input order, centered per column
links drawn in input order: order is part of the spec

Never do this

links whose widths change between ends
crossing minimization by randomization
cycles
more than 3 columns

QA before delivering

per-node conservation
adjacent-column links only
input order preserved
source present

Data shape

title	action title with a number
source	bottom-left always
unit	on first node label
columns	[{name, nodes: [{name, value}]}] 2-3 columns
links	[{from, to, value}] adjacent columns only

Sample data (golden)

{
  "title": "Road carries 70 of 130 loads; barge stays marginal",
  "eyebrow": "ORIGIN TO ROUTE . JUNE",
  "source": "Source: sample dataset v1, 2026-07-12",
  "unit": "loads",
  "columns": [
    {
      "name": "Origin",
      "nodes": [
        {
          "name": "Supplier A",
          "value": 60
        },
        {
          "name": "Supplier B",
          "value": 40
        },
        {
          "name": "Supplier C",
          "value": 30
        }
      ]
    },
    {
      "name": "Route",
      "nodes": [
        {
          "name": "Road",
          "value": 70
        },
        {
          "name": "Rail",
          "value": 40
        },
        {
          "name": "Barge",
          "value": 20
        }
      ]
    }
  ],
  "links": [
    {
      "from": "Supplier A",
      "to": "Road",
      "value": 35
    },
    {
      "from": "Supplier A",
      "to": "Rail",
      "value": 25
    },
    {
      "from": "Supplier B",
      "to": "Road",
      "value": 25
    },
    {
      "from": "Supplier B",
      "to": "Barge",
      "value": 15
    },
    {
      "from": "Supplier C",
      "to": "Road",
      "value": 10
    },
    {
      "from": "Supplier C",
      "to": "Rail",
      "value": 15
    },
    {
      "from": "Supplier C",
      "to": "Barge",
      "value": 5
    }
  ]
}