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Maps

Flow Map

type: 'flowmap'

Directional, tapered curved bands between two geographic endpoints. Endpoints are either [lon, lat] pairs or the id of a point in a sibling mappoint series; band thickness scales with each link's weight and an arrowhead marks the destination.

Edit the JSON on the right and press Run (or ⌘/Ctrl + Enter) — data, titles, categories and colors all update live.

Live
Flow Map
Edit · JSON

Data format

{ from, to, weight } · [from, to, weight] (from/to: point id or [lon,lat])

Data shape

The JSON you pass inside the chart — drop it straight into your series.

data: [
  ['London', 'New York', 8],
  ['Tokyo', 'Sydney', 5],
  ['São Paulo', 'London', 4]
]

Example

import KatuCharts from 'katucharts.js';

KatuCharts.chart('container', {
  chart: { type: 'map' },
  chart: { type: 'map', map: world },
  series: [
    { type: 'map', mapData: world, data: [] },
    { type: 'mappoint', data: [
      { id: 'London', lat: 51.5, lon: -0.12 },
      { id: 'New York', lat: 40.71, lon: -74 }
    ] },
    {
      type: 'flowmap', width: 14,
      data: [
        ['London', 'New York', 8],
        ['Tokyo', 'Sydney', 5]
      ]
    }
  ]
});

Type-specific options

OptionDescription
from / toEndpoints: a mappoint id or a [lon, lat] pair.
weightRelative link magnitude → band thickness.
widthMax band width in pixels.
curveFactorSideways bow of the curve (default 0.3).
fillOpacityBand fill opacity.

Common errors

Why does my flow map chart render as a line chart?
The chart type was not registered. KatuCharts logs "KatuCharts: unknown series type "<type>", falling back to line" and draws a line chart rather than throwing. Import the module the type belongs to — for example `import 'katucharts.js/bio';` — before creating the chart.
Why do I get "Cannot read properties of null (reading 'appendChild')"?
The container element does not exist when the chart is created. Create the chart after the element is in the DOM: in React that means inside useEffect, not during render.
Why is the chart rendering with zero height?
The container has no height. A div with no content collapses to zero. Give it a height in CSS, or pass `chart: { height: 400 }` in the options.

FAQ

How do I create a flow map chart in JavaScript?
Install with `npm install katucharts.js`, then call KatuCharts.chart(container, { chart: { type: 'flowmap' }, series: [...] }).
Why does my flow map chart render as a line chart?
The chart type was not registered. KatuCharts logs "KatuCharts: unknown series type "<type>", falling back to line" and draws a line chart rather than throwing. Import the module the type belongs to — for example `import 'katucharts.js/bio';` — before creating the chart.
Why do I get "Cannot read properties of null (reading 'appendChild')"?
The container element does not exist when the chart is created. Create the chart after the element is in the DOM: in React that means inside useEffect, not during render.
Why is the chart rendering with zero height?
The container has no height. A div with no content collapses to zero. Give it a height in CSS, or pass `chart: { height: 400 }` in the options.
Common options (color, visible, marker, dataLabels, animation, events, zones…) apply to every type — see Configuration → series. See it rendered in the gallery.