Graflume · Alpha

Heatmap · Edge-case application

Encode intensity for two categorical dimensions as a nearly continuous color matrix. Exercise numeric range, sparse structure, and large inputs with valid data. Each tab materializes data only when needed and never silently repairs invalid values.

Chart family · Advanced families

Heatmap

Encode intensity for two categorical dimensions as a nearly continuous color matrix.

Quick API
heatmap()
Browser snapshot
graflume/complete
mark
heatmap
Presets
2

Edge cases

Numeric range, irregular structure, and data volume

Exercise numeric range, sparse structure, and large inputs with valid data. Each tab materializes data only when needed and never silently repairs invalid values.

Wide numeric range

Mix zero, very small finite values, and very large finite values to verify automatic domains, precision, and stable geometry. NaN and Infinity remain intentionally invalid. It applies 2 data-integrity rules that preserve finite values and axis domains.

StatusLoading

  • extreme-range
  • extreme-small
  • extreme-large
  • zero
  • mixed-sign
  • budget:marks<=6
Graflume.heatmap() Canvas 2D
Control help

Zoom and pan inspect the rendered surface without changing data axes or values. When playback controls are available, they move through real steps in the order each unique value first appears in the source data.

Use Tab to reach a control and Enter or Space to activate it. With the chart focused, use plus and minus to zoom and arrow keys to pan.

Auto placement compares perimeter candidates and avoids the plot, legend, and other callouts when possible. Explicit placement is preserved with only necessary safety correction. Callout text wraps safely inside the bubble. Long unbroken tokens are visually shortened within the line budget, while the complete source text remains available to assistive technology.

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Browser API · Portable schema

Browser API

Graflume.heatmap()

const data = [
  {
    "value": -1000000000000,
    "x": 0,
    "y": 0
  },
  {
    "value": -1e-9,
    "x": 1,
    "y": 0
  },
  {
    "value": 0,
    "x": 2,
    "y": 0
  },
  {
    "value": 1000000000000,
    "x": 3,
    "y": 0
  },
  {
    "value": 1e-9,
    "x": 4,
    "y": 0
  },
  {
    "value": 1000000,
    "x": 5,
    "y": 0
  }
];

const options = {
  "accessibility": {
    "description": "Two hotspots and a diagonal ridge form a purposeful density landscape. The example uses curated, deterministic data and exposes its exact values in a semantic table.",
    "label": "Heatmap"
  },
  "height": 620,
  "locale": "en",
  "title": {
    "subtitle": "edge case · range",
    "text": "Heatmap"
  },
  "width": "container",
  "x": {
    "field": "x",
    "title": "Horizontal bin",
    "type": "quantitative"
  },
  "y": {
    "field": "y",
    "scale": {
      "constant": 1,
      "type": "symlog"
    },
    "title": "Vertical bin",
    "type": "quantitative"
  }
};

Graflume.heatmap('#chart', data, options);

Portable schema

ChartSpec 0.1 · options

{
  "accessibility": {
    "description": "Two hotspots and a diagonal ridge form a purposeful density landscape. The example uses curated, deterministic data and exposes its exact values in a semantic table.",
    "label": "Heatmap"
  },
  "height": 620,
  "locale": "en",
  "title": {
    "subtitle": "edge case · range",
    "text": "Heatmap"
  },
  "width": "container",
  "x": {
    "field": "x",
    "title": "Horizontal bin",
    "type": "quantitative"
  },
  "y": {
    "field": "y",
    "scale": {
      "constant": 1,
      "type": "symlog"
    },
    "title": "Vertical bin",
    "type": "quantitative"
  }
}
Chart catalog