9, 20
                        ],
// Transition from heatmap to circle layer by zoom level
                        'heatmap-opacity': [
                            'interpolate',
                            ['linear'],['zoom'],
                            7.5, 1,
                            9, 0
                        ]
                    }
                }
            );

            map.addSource('mouseoversource', {
                    type: 'geojson',
                    data: {
                      