ayer with a special pointToLayer function
// that'll generate scaled points.
var earthquakesLayer = L.geoJson(null, { pointToLayer: scaledPoint })
    .addTo(map);

function pointColor(feature) {
    return feature.properties.mag > 5 ? '#f55' : '#a00';
}

function pointRadius(feature) {
    return (feature.properties.mag - 4) * 10;
}

function scaledPoint(feature, latlng) {
    return L.circleMarker(latlng, {
        radius: pointRadius(feature),
        fillColor: pointColor(feature),
        fillOpacity: 