0.7,
        weight: 0.5,
        color: '#fff'
    }).bindPopup(
        '<h2>' + feature.properties.place + '</h2>' +
        '<h3>' + new Date(feature.properties.time) + '</h3>' +
        feature.properties.mag + ' magnitude');
}

// Request our data and add it to the earthquakesLayer.
d3.json('{{site.baseurl}}/assets/data/earthquakes.geojson', function(err, data) {
    earthquakesLayer.addData(data);
    setBrush(data);
});

function setBrush(data) {
    var container = d3.select('#brush'),
        widt