Packed Bubble Chart Example
A packed bubble chart displays relatively sized circles arbitrarily packed together. You can change the shape of the packing by adjusting the x or y gravity. This example shows dummy categorical data where node areas are proportional to the amount value.
Vega JSON Specification <>
{
"$schema": "https://vega.github.io/schema/vega/v5.json",
"width": 800,
"height": 500,
"padding": {"left": 5, "right": 5, "top": 20, "bottom": 0},
"autosize": "none",
"signals": [
{"name": "cx", "update": "width / 2"},
{"name": "cy", "update": "height / 2"},
{
"name": "gravityX",
"value": 0.2,
"bind": {"input": "range", "min": 0, "max": 1}
},
{
"name": "gravityY",
"value": 0.1,
"bind": {"input": "range", "min": 0, "max": 1}
}
],
"data": [
{
"name": "table",
"values": [
{"category": "A", "amount": 0.28},
{"category": "B", "amount": 0.55},
{"category": "C", "amount": 0.43},
{"category": "D", "amount": 0.91},
{"category": "E", "amount": 0.81},
{"category": "F", "amount": 0.53},
{"category": "G", "amount": 0.19},
{"category": "H", "amount": 0.87},
{"category": "I", "amount": 0.28},
{"category": "J", "amount": 0.55},
{"category": "K", "amount": 0.43},
{"category": "L", "amount": 0.91},
{"category": "M", "amount": 0.81},
{"category": "N", "amount": 0.53},
{"category": "O", "amount": 0.19},
{"category": "P", "amount": 0.87}
]
}
],
"scales": [
{
"name": "size",
"domain": {"data": "table", "field": "amount"},
"range": [100, 3000]
},
{
"name": "color",
"type": "ordinal",
"domain": {"data": "table", "field": "category"},
"range": "ramp"
}
],
"marks": [
{
"name": "nodes",
"type": "symbol",
"from": {"data": "table"},
"encode": {
"enter": {
"fill": {"scale": "color", "field": "category"},
"xfocus": {"signal": "cx"},
"yfocus": {"signal": "cy"}
},
"update": {
"size": {"signal": "pow(2 * datum.amount, 2)", "scale": "size"},
"stroke": {"value": "white"},
"strokeWidth": {"value": 1},
"tooltip": {"signal": "datum"}
}
},
"transform": [
{
"type": "force",
"iterations": 100,
"static": false,
"forces": [
{
"force": "collide",
"iterations": 2,
"radius": {"expr": "sqrt(datum.size) / 2"}
},
{"force": "center", "x": {"signal": "cx"}, "y": {"signal": "cy"}},
{"force": "x", "x": "xfocus", "strength": {"signal": "gravityX"}},
{"force": "y", "y": "yfocus", "strength": {"signal": "gravityY"}}
]
}
]
},
{
"type": "text",
"from": {"data": "nodes"},
"encode": {
"enter": {
"align": {"value": "center"},
"baseline": {"value": "middle"},
"fontSize": {"value": 15},
"fontWeight": {"value": "bold"},
"fill": {"value": "white"},
"text": {"field": "datum.category"}
},
"update": {"x": {"field": "x"}, "y": {"field": "y"}}
}
}
]
}