javascript - 谷歌热图梯度范围？

Question

我得到了城市人群的热图图层，我需要对热图上的人群进行排序，如何动态更改 Google 热图梯度？

var heatMapData = [
  {location: new google.maps.LatLng(37.782, -122.447), weight: 50},
  new google.maps.LatLng(37.782, -122.445),
  {location: new google.maps.LatLng(37.782, -122.443), weight: 20},
  {location: new google.maps.LatLng(37.782, -122.441), weight: 30},
  {location: new google.maps.LatLng(37.782, -122.439), weight: 20},
  new google.maps.LatLng(37.782, -122.437),
  {location: new google.maps.LatLng(37.782, -122.435), weight: 55},

  {location: new google.maps.LatLng(37.785, -122.447), weight: 30},
  {location: new google.maps.LatLng(37.785, -122.445), weight: 20},
  new google.maps.LatLng(37.785, -122.443),
  {location: new google.maps.LatLng(37.785, -122.441), weight: 86},
  new google.maps.LatLng(37.785, -122.439),
  {location: new google.maps.LatLng(37.785, -122.437), weight: 20},
  {location: new google.maps.LatLng(37.785, -122.435), weight: 20}
];

var sanFrancisco = new google.maps.LatLng(37.774546, -122.433523);

map = new google.maps.Map(document.getElementById('map-canvas'), {
  center: sanFrancisco,
  zoom: 13,
  mapTypeId: google.maps.MapTypeId.SATELLITE
});

var heatmap = new google.maps.visualization.HeatmapLayer({
  data: heatMapData
});
heatmap.setMap(map);

例如:我在热图上看起来的范围是 20 到 40？

Answer 1

使用此命令。更多信息here

 function changeGradient() {
    var gradient = [
      'rgba(0, 255, 255, 0)',
      'rgba(0, 255, 255, 1)',
      'rgba(0, 191, 255, 1)',
      'rgba(0, 127, 255, 1)',
      'rgba(0, 63, 255, 1)',
      'rgba(0, 0, 255, 1)',
      'rgba(0, 0, 223, 1)',
      'rgba(0, 0, 191, 1)',
      'rgba(0, 0, 159, 1)',
      'rgba(0, 0, 127, 1)',
      'rgba(63, 0, 91, 1)',
      'rgba(127, 0, 63, 1)',
      'rgba(191, 0, 31, 1)',
      'rgba(255, 0, 0, 1)'
    ]
    heatmap.set('gradient', heatmap.get('gradient') ? null : gradient);
  }