如何识别点击的地图区域的几何坐标

Question

我有一个使用城市 json 文件的谷歌地图：

javascript：

var infoWindow = new google.maps.InfoWindow();
map = new google.maps.Map(document.getElementById("map_canvas"),myOptions);
map.data.loadGeoJson('js/neighborhoods_geojson2.json');

json 看起来像这样：

{
    "type": "FeatureCollection",
    "features": [
        {    
           {
            "type": "Feature",
            "properties": {
                "name": "muniname",
                "created_at": "2013-02-19T19:11:52.458Z",
                "updated_at": "2013-02-19T19:11:52.719Z",
                "cartodb_id": 50,
                "population": "1,785",
                "beds": "20", "bedsratio": "11.20" 
            },
            "geometry": {
                "type": "MultiPolygon",
                "coordinates": [
                     (coordinate pairs go here)
                ]
            }
        },
(next municipality)
 ]
}

我希望能够将鼠标悬停在一个自治市上并获得一个信息窗口。但是如何确定市的坐标呢？

 map.data.addListener('mouseover', function (e) {
    var thisMuni = e.feature.geometry.getProperty('coordinates'); //doesn't work
    strContent = "<h2>" + e.feature.getProperty('name') + "</h2>\
        <table>\
        <tr><td>Population</td><td class='population'>" + e.feature.getProperty('population') + "</td></tr>\
        <tr><td>Beds</td><td class='beds'>" + e.feature.getProperty('beds') + "</td></tr>\
        <tr><td>Beds per 1000</td><td class='bedsratio'>" + e.feature.getProperty('bedsratio') + "</td></tr>\
        </table>";
        infoWindow.open(map, this); //infowindow doesn't pop up on municipality
});

如何识别地图上的自治市，以便在其上弹出信息窗口？

Answer 1

如果你不是在marker上打开信息窗口，你不能使用第二个参数打开，你必须自己设置信息窗口的位置。

map.data.addListener('mouseover', function (e) {
    var strContent = "<h2>" + e.feature.getProperty('name') + "</h2>\
        <table>\
        <tr><td>Population</td><td class='population'>" + e.feature.getProperty('population') + "</td></tr>\
        <tr><td>Beds</td><td class='beds'>" + e.feature.getProperty('beds') + "</td></tr>\
        <tr><td>Beds per 1000</td><td class='bedsratio'>" + e.feature.getProperty('bedsratio') + "</td></tr>\
        </table>";
    infoWindow.setPosition(e.latLng);
    infoWindow.setContent(strContent);
    infoWindow.open(map);
});

代码 sn-p：

var map;
var infoWindow = new google.maps.InfoWindow();

function initMap() {
  map = new google.maps.Map(document.getElementById('map'), {
    zoom: 4,
    center: {
      lat: -28,
      lng: 137
    }
  });

  // Load GeoJSON.
  map.data.addGeoJson(googleJson);

  // [START snippet]
  // Color each letter gray. Change the color when the isColorful property
  // is set to true.
  map.data.setStyle(function(feature) {
    var color = 'gray';
    if (feature.getProperty('isColorful')) {
      color = feature.getProperty('color');
    }
    return /** @type {google.maps.Data.StyleOptions} */ ({
      fillColor: color,
      strokeColor: color,
      strokeWeight: 2
    });
  });

  // When the user clicks, set 'isColorful', changing the color of the letters.
  map.data.addListener('click', function(event) {
    event.feature.setProperty('isColorful', true);
  });

  // When the user hovers, tempt them to click by outlining the letters.
  // Call revertStyle() to remove all overrides. This will use the style rules
  // defined in the function passed to setStyle()
  map.data.addListener('mouseover', function(event) {
    map.data.revertStyle();
    map.data.overrideStyle(event.feature, {
      strokeWeight: 8
    });
  });
  map.data.addListener('mouseover', function(e) {
    var strContent = "<h2>" + e.feature.getProperty('name') + "</h2>\
        <table>\
        <tr><td>Population</td><td class='population'>" + e.feature.getProperty('population') + "</td></tr>\
        <tr><td>Beds</td><td class='beds'>" + e.feature.getProperty('beds') + "</td></tr>\
        <tr><td>Beds per 1000</td><td class='bedsratio'>" + e.feature.getProperty('bedsratio') + "</td></tr>\
        </table>";
    infoWindow.setPosition(e.latLng);
    infoWindow.setContent(strContent);
    infoWindow.open(map);
  });

  map.data.addListener('mouseout', function(event) {
    map.data.revertStyle();
  });
  // [END snippet]
}
google.maps.event.addDomListener(window, "load", initMap);
var googleJson = {
  "type": "FeatureCollection",
  "features": [{
    "type": "Feature",
    "properties": {
      "letter": "G",
      "color": "blue",
      "rank": "7",
      "ascii": "71",
      "name": "muniname",
      "created_at": "2013-02-19T19:11:52.458Z",
      "updated_at": "2013-02-19T19:11:52.719Z",
      "cartodb_id": 50,
      "population": "2,500",
      "beds": "25",
      "bedsratio": "11.20"
    },
    "geometry": {
      "type": "Polygon",
      "coordinates": [
        [
          [123.61, -22.14],
          [122.38, -21.73],
          [121.06, -21.69],
          [119.66, -22.22],
          [119.00, -23.40],
          [118.65, -24.76],
          [118.43, -26.07],
          [118.78, -27.56],
          [119.22, -28.57],
          [120.23, -29.49],
          [121.77, -29.87],
          [123.57, -29.64],
          [124.45, -29.03],
          [124.71, -27.95],
          [124.80, -26.70],
          [124.80, -25.60],
          [123.61, -25.64],
          [122.56, -25.64],
          [121.72, -25.72],
          [121.81, -26.62],
          [121.86, -26.98],
          [122.60, -26.90],
          [123.57, -27.05],
          [123.57, -27.68],
          [123.35, -28.18],
          [122.51, -28.38],
          [121.77, -28.26],
          [121.02, -27.91],
          [120.49, -27.21],
          [120.14, -26.50],
          [120.10, -25.64],
          [120.27, -24.52],
          [120.67, -23.68],
          [121.72, -23.32],
          [122.43, -23.48],
          [123.04, -24.04],
          [124.54, -24.28],
          [124.58, -23.20],
          [123.61, -22.14]
        ]
      ]
    }
  }, {
    "type": "Feature",
    "properties": {
      "letter": "o",
      "color": "red",
      "rank": "15",
      "ascii": "111",
      "name": "muniname1",
      "created_at": "2013-02-19T19:11:52.458Z",
      "updated_at": "2013-02-19T19:11:52.719Z",
      "cartodb_id": 51,
      "population": "3,000",
      "beds": "23",
      "bedsratio": "11.22"
    },
    "geometry": {
      "type": "Polygon",
      "coordinates": [
        [
          [128.84, -25.76],
          [128.18, -25.60],
          [127.96, -25.52],
          [127.88, -25.52],
          [127.70, -25.60],
          [127.26, -25.79],
          [126.60, -26.11],
          [126.16, -26.78],
          [126.12, -27.68],
          [126.21, -28.42],
          [126.69, -29.49],
          [127.74, -29.80],
          [128.80, -29.72],
          [129.41, -29.03],
          [129.72, -27.95],
          [129.68, -27.21],
          [129.33, -26.23],
          [128.84, -25.76]
        ],
        [
          [128.45, -27.44],
          [128.32, -26.94],
          [127.70, -26.82],
          [127.35, -27.05],
          [127.17, -27.80],
          [127.57, -28.22],
          [128.10, -28.42],
          [128.49, -27.80],
          [128.45, -27.44]
        ]
      ]
    }
  }, {
    "type": "Feature",
    "properties": {
      "letter": "o",
      "color": "yellow",
      "rank": "15",
      "ascii": "111",
      "name": "muniname2",
      "created_at": "2013-02-19T19:11:52.458Z",
      "updated_at": "2013-02-19T19:11:52.719Z",
      "cartodb_id": 52,
      "population": "4,000",
      "beds": "23",
      "bedsratio": "11.23"
    },
    "geometry": {
      "type": "Polygon",
      "coordinates": [
        [
          [131.87, -25.76],
          [131.35, -26.07],
          [130.95, -26.78],
          [130.82, -27.64],
          [130.86, -28.53],
          [131.26, -29.22],
          [131.92, -29.76],
          [132.45, -29.87],
          [133.06, -29.76],
          [133.72, -29.34],
          [134.07, -28.80],
          [134.20, -27.91],
          [134.07, -27.21],
          [133.81, -26.31],
          [133.37, -25.83],
          [132.71, -25.64],
          [131.87, -25.76]
        ],
        [
          [133.15, -27.17],
          [132.71, -26.86],
          [132.09, -26.90],
          [131.74, -27.56],
          [131.79, -28.26],
          [132.36, -28.45],
          [132.93, -28.34],
          [133.15, -27.76],
          [133.15, -27.17]
        ]
      ]
    }
  }, {
    "type": "Feature",
    "properties": {
      "letter": "g",
      "color": "blue",
      "rank": "7",
      "ascii": "103",
      "name": "muniname",
      "created_at": "2013-02-19T19:11:52.458Z",
      "updated_at": "2013-02-19T19:11:52.719Z",
      "cartodb_id": 55,
      "population": "1,000",
      "beds": "25",
      "bedsratio": "11.24"
    },
    "geometry": {
      "type": "Polygon",
      "coordinates": [
        [
          [138.12, -25.04],
          [136.84, -25.16],
          [135.96, -25.36],
          [135.26, -25.99],
          [135, -26.90],
          [135.04, -27.91],
          [135.26, -28.88],
          [136.05, -29.45],
          [137.02, -29.49],
          [137.81, -29.49],
          [137.94, -29.99],
          [137.90, -31.20],
          [137.85, -32.24],
          [136.88, -32.69],
          [136.45, -32.36],
          [136.27, -31.80],
          [134.95, -31.84],
          [135.17, -32.99],
          [135.52, -33.43],
          [136.14, -33.76],
          [137.06, -33.83],
          [138.12, -33.65],
          [138.86, -33.21],
          [139.30, -32.28],
          [139.30, -31.24],
          [139.30, -30.14],
          [139.21, -28.96],
          [139.17, -28.22],
          [139.08, -27.41],
          [139.08, -26.47],
          [138.99, -25.40],
          [138.73, -25.00],
          [138.12, -25.04]
        ],
        [
          [137.50, -26.54],
          [136.97, -26.47],
          [136.49, -26.58],
          [136.31, -27.13],
          [136.31, -27.72],
          [136.58, -27.99],
          [137.50, -28.03],
          [137.68, -27.68],
          [137.59, -26.78],
          [137.50, -26.54]
        ]
      ]
    }
  }, {
    "type": "Feature",
    "properties": {
      "letter": "l",
      "color": "green",
      "rank": "12",
      "ascii": "108",
      "name": "muniname5",
      "created_at": "2013-02-19T19:11:52.458Z",
      "updated_at": "2013-02-19T19:11:52.719Z",
      "cartodb_id": 60,
      "population": "500",
      "beds": "15",
      "bedsratio": "12.0"
    },
    "geometry": {
      "type": "Polygon",
      "coordinates": [
        [
          [140.14, -21.04],
          [140.31, -29.42],
          [141.67, -29.49],
          [141.59, -20.92],
          [140.14, -21.04]
        ]
      ]
    }
  }, {
    "type": "Feature",
    "properties": {
      "letter": "e",
      "color": "red",
      "rank": "5",
      "ascii": "101",
      "name": "muniname6",
      "created_at": "2013-02-19T19:11:52.458Z",
      "updated_at": "2013-02-19T19:11:52.719Z",
      "cartodb_id": 70,
      "population": "10,000",
      "beds": "200",
      "bedsratio": "11.27"
    },
    "geometry": {
      "type": "Polygon",
      "coordinates": [
        [
          [144.14, -27.41],
          [145.67, -27.52],
          [146.86, -27.09],
          [146.82, -25.64],
          [146.25, -25.04],
          [145.45, -24.68],
          [144.66, -24.60],
          [144.09, -24.76],
          [143.43, -25.08],
          [142.99, -25.40],
          [142.64, -26.03],
          [142.64, -27.05],
          [142.64, -28.26],
          [143.30, -29.11],
          [144.18, -29.57],
          [145.41, -29.64],
          [146.46, -29.19],
          [146.64, -28.72],
          [146.82, -28.14],
          [144.84, -28.42],
          [144.31, -28.26],
          [144.14, -27.41]
        ],
        [
          [144.18, -26.39],
          [144.53, -26.58],
          [145.19, -26.62],
          [145.72, -26.35],
          [145.81, -25.91],
          [145.41, -25.68],
          [144.97, -25.68],
          [144.49, -25.64],
          [144, -25.99],
          [144.18, -26.39]
        ]
      ]
    }
  }]
};

html,
body {
  height: 100%;
  margin: 0;
  padding: 0;
}

#map {
  height: 100%;
}

<script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk"></script>
<div id="map"></div>