An example of a standalone react-map-gl-overlay. Use it as a starting point for creating your own custom overlay.
var ExampleOverlay = require('react-map-gl-example-overlay');
var cities = require('example-cities');
Where each element in cities
has the form: {latitude, longitude}
.
render() {
var {viewport} = this.state.viewport;
return <MapGL {...viewport}>
<ExampleOverlay {...viewport} locations={cities} />
</MapGL>;
}