Google Maps打开infowindow选择的geojson数据

Question

我在地图上创建了两个不同的geojson数据。我想点击选定的geojson数据。我使用这个代码工作，但我得到两个geojson id没有点击id。我只是想点击geojson id。这里f1是一个已定义的属性。

map.data.addListener('click', function(event){
   var id=event.feature.getProperty('f1');
    alert(id);
    infowindow2.setContent(sContent);
    infowindow2.setPosition(event.latLng);
    infowindow2.setOptions({pixelOffset: new google.maps.Size(0,-34)});
    infowindow2.open(map);
}

İt是geojson数据的例子

{
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "geometry": {
        "type": "Polygon",
        "coordinates": [
          [
            [
              28.9707230069957,
              41.0143811020089
            ],
            [
              28.9707162564384,
              41.0143424956501
            ],
            [
              28.9707099456323,
              41.0143003832993
            ],
            [
              28.9707027979273,
              41.0142558268809
            ],
            [
              28.970696368278,
              41.0142152406152
            ],
            [
              28.9706905696604,
              41.0141716903304
            ],
            [
              28.9706439363613,
              41.0141812741487
            ],
            [
              28.9706538187623,
              41.0142586346452
            ],
            [
              28.9706604147999,
              41.0143007495466
            ],
            [
              28.9706724204532,
              41.0143865085056
            ],
            [
              28.9707230069957,
              41.0143811020089
            ]
          ]
        ]
      },
      "properties": {
        "f1": 110013011,
        "f2": "FATİH",
        "f3": "SURURİ",
        "f4": "F21C25D2C",
        "f5": "P29",
        "f6": "337",
        "f7": "34",
        "f8": "1. Derece Koruma Bolgeleri",
        "f9": null,
        "f10": "Ş",
        "f11": 55,
        "f12": 96,
        "f13": 1121229337,
        "f14": 12,
        "f15": 28.9706822916352,
        "f16": 41.0142812568067,
        "f17": 12,
        "f18": 12,
        "f19": 227,
        "f20": "SURURİ",
        "f21": "e17c8db4-bec3-11e5-b590-00a0d1e9ad00",
        "f22": 10598737,
        "f23": 20598781,
        "f24": "e17c66a4-bec3-11e5-8eec-00a0d1e9ad00"
      }
    }
  ]
}