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Creating Dorling Cartograms

It's a small step from a Bubble symbol map to a Dorling cartogram. At first you set up your base map layer.

map.addLayer('regions', {
    key: 'id'  // define which feature attribute holds the unique identifiers

It's up to you whether you want to show the geographical map or not. If you don't want to, just set the opacity to zero.

map.addLayer('regions', {
    key: 'id',
    styles: {
        opacity: 0

Now add symbols of the type Bubble to your map.

symbols = map.addSymbols({
    type: kartograph.Bubble,
    data: ...
    location: function(d) {
        // return id of a map layer path to position
        // the symbol on its centroid
        return 'mylayer.' + d.pathId;
    radius: function(d) {
        // define radius depending on some data, e.g. population
        return Math.sqrt(d.population / maxPop) * 30;

Last thing you need to do is to run the dorlingLayout helper on your symbols: