如何将 GeoJSON(MultiLineString) 图层添加到 Google 地图

Question

我需要创建将 GeoJSON 数据（MultiLineString 格式）用作 Google 地图上的数据层的地图。我创建了一个 Google Maps JavaScript API 项目，并拥有一个 API 密钥。

我尝试了以下示例：

示例一：
https://developers.google.com/maps/documentation/javascript/examples/layer-data-simple
（这会呈现一个多边形，但似乎不支持 MultiLineString 的样式）。

示例二：
https://developers.google.com/maps/documentation/javascript/examples/layer-data-dragndrop
（此示例允许通过拖放添加 GeoJSON，但我看不到如何保存地图和数据层。）

来自http://geojsonlint.com 的 GeoJSON MultiLineString 示例：

{
    "type": "MultiLineString",
    "coordinates": [
        [
            [
                -105.0214433670044,
                39.57805759162015
            ],
            [
                -105.02150774002075,
                39.57780951131517
            ],
            [
                -105.02157211303711,
                39.57749527498758
            ],
            [
                -105.02157211303711,
                39.57716449836683
            ],
            [
                -105.02157211303711,
                39.57703218727656
            ],
            [
                -105.02152919769287,
                39.57678410330158
            ]
        ],
        [
            [
                -105.01989841461182,
                39.574997872470774
            ],
            [
                -105.01959800720215,
                39.57489863607502
            ],
            [
                -105.01906156539916,
                39.57478286010041
            ]
        ],
        [
            [
                -105.01717329025269,
                39.5744024519653
            ],
            [
                -105.01698017120361,
                39.574385912433804
            ],
            [
                -105.0166368484497,
                39.574385912433804
            ],
            [
                -105.01650810241699,
                39.5744024519653
            ],
            [
                -105.0159502029419,
                39.574270135602866
            ]
        ],
        [
            [
                -105.0142765045166,
                39.57397242286402
            ],
            [
                -105.01412630081175,
                39.57403858136094
            ],
            [
                -105.0138258934021,
                39.57417089816531
            ],
            [
                -105.01331090927124,
                39.57445207053608
            ]
        ]
    ]
}

Answer 1

您可以像这样添加 GeoJSON

function loadGeoJsonString(geoString) {
  var geojson = JSON.parse(geoString);
  map.data.addGeoJson(geojson);
}

有

map.data.setStyle({
  //Put styling here
});

您可以为添加的 GeoJSON 设置样式。因此，当您加载 GeoJSON 时不会应用样式，但您可以在之后添加它。

Answer 2

关注example in the documentation

数据类

google.maps.Data 类

用于显示地理空间数据的图层。可以显示点、线串和多边形。

默认情况下，每个 Map 都有一个 Data 对象，因此大多数时候不需要构造一个。例如：

var myMap = new google.maps.Map(...);
myMap.data.addGeoJson(...);
myMap.data.setStyle(...); 

proof of concept fiddle

代码 sn-p：

function initialize() {
  var map = new google.maps.Map(
    document.getElementById("map_canvas"), {
      center: new google.maps.LatLng(37.4419, 70.1419),
      zoom: 3,
      mapTypeId: google.maps.MapTypeId.ROADMAP
    });
  map.data.addGeoJson(jsonData);
  map.data.setStyle({
    strokeColor: "blue"
  })

}
google.maps.event.addDomListener(window, "load", initialize);
var jsonData = {
  "type": "FeatureCollection",
  "features": [{
    "type": "Feature",
    "properties": {
      "stroke": "#555555",
      "stroke-width": 2,
      "stroke-opacity": 1
    },
    "geometry": {
      "type": "LineString",
      "coordinates": [
        [
          79.8046875,
          45.583289756006316
        ],
        [
          73.828125,
          48.922499263758255
        ],
        [
          72.421875,
          46.07323062540838
        ],
        [
          72.0703125,
          42.553080288955826
        ],
        [
          79.453125,
          41.77131167976407
        ],
        [
          78.046875,
          37.71859032558816
        ],
        [
          72.7734375,
          34.016241889667015
        ],
        [
          66.796875,
          39.63953756436671
        ],
        [
          66.4453125,
          48.45835188280866
        ],
        [
          74.1796875,
          53.74871079689897
        ],
        [
          55.1953125,
          55.7765730186677
        ],
        [
          49.92187499999999,
          48.69096039092549
        ],
        [
          50.625,
          40.17887331434696
        ]
      ]
    }
  }]
};

html,
body,
#map_canvas {
  height: 100%;
  width: 100%;
  margin: 0px;
  padding: 0px
}

<script src="https://maps.googleapis.com/maps/api/js"></script>
<div id="map_canvas"></div>