Hackstreetboys IceHero Creating HeatMaps

heatmaps.js

heatmap = new google.maps.visualization.HeatmapLayer({
          data: getPoints(),
          map: map
        });

    function getPoints() {
        var returnVal = [];

        $.getJSON( "https://prayashm97.github.io/js/ajax/testfile.json", function( data ) {
          $.each( data, function( key, val ) {
              x = {
                  'location':new google.maps.LatLng(val.Latitude,val.Longitude), 'weight': (((val.CO2)-371)/16)
              }


              returnVal.push(x)
          });
        })
        .error(function(err) { console.error(err)});
        return(returnVal);
    };