Question

我在地图上工作，我根据来自JSON API的数据异步创建GeoJSON图层。我的初始数据加载工作，并查看GeoJSON对象，它似乎添加了额外的元素。

但是，如果我然后尝试使用相同的源（指向更新的GeoJSON对象的数据元素）调用map.getSource（...）。setData（...），我得到

错误：TypeError：无法读取属性＆＃39; length＆＃39;未定义的在Actor.receive（actor.js：77）

我在网上找到的唯一引用与尝试在不再存在的样式上调用setData或具有无效的GeoJSON数据有关，但似乎并非如此 - 例如。

> map.getSource("advertisers");
e {id: "advertisers", type: "geojson", minzoom: 0, maxzoom: 18, tileSize: 512, …}
> features;
(7634) [{…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, …]
> features[0];
{type: "Feature", geometry: {…}, properties: {…}} 
> features[0].geometry;
{type: "Point", coordinates: Array(2)}
> map.getSource("advertisers").setData(features);
e {id: "advertisers", type: "geojson", minzoom: 0, maxzoom: 18, tileSize: 512, …}
evented.js:111 Error: TypeError: Cannot read property 'length' of undefined
at Actor.receive (actor.js:77)

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Answer 1

看起来你正在向setData()传递一系列功能，但你需要传递一个有效的GeoJSON对象。

您应该替换：map.getSource("advertisers").setData(features);

使用：

map.getSource("advertisers").setData({
  type: 'FeatureCollection',
  features: features
});

调用map.getSource（...）。setData（...）会导致TypeError：无法读取属性＆＃39; length＆＃39;未定义的

1 个答案: