Question

我试图在互联网上找到这个问题的答案。我发现了一个similar question，但似乎没有人能够给出正确答案。

我在Google Maps API网站https://developers.google.com/maps/documentation/javascript/combining-data上尝试了一个示例。我只对您的代码进行了一些更改，以便将人口普查数据用于其他国家/地区。
我更改了链接，以便访问我自己的json文件。在region.geojson中，您拥有土耳其各省的所有坐标，在test.json中，您拥有每个省的人口普查数据。
我将人口普查数据放在相同的格式中，但是当loadCensusData函数命中时 map.data .getFeatureById（STATEID） .setProperty（'census_variable'，censusVariable）;

迭代它时给出了以下错误，“Uncaught TypeError：无法读取未定义的属性'setProperty'”。如果我对此进行评论，它将继续迭代直到它结束，但问题是我将无法使用'census_variable'，因为它尚未设置。 4.如果我更改链接以指回美国人口普查数据，它将按预期再次运行。

我有什么想法可以解决这个错误？或者你知道造成这种情况的原因吗？

请参阅下面我的地图代码：

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
    <title>Mashups with google.maps.Data</title>
    <style>
      html, body, #map { height: 100%; margin: 0; padding: 0; overflow: hidden; }
        .nicebox {
          position: absolute;
          text-align: center;
          font-family: "Roboto", "Arial", sans-serif;
          font-size: 13px;
          z-index: 5;
          box-shadow: 0 4px 6px -4px #333;
          padding: 5px 10px;
          background: rgb(255,255,255);
          background: linear-gradient(to bottom,rgba(255,255,255,1) 0%,rgba(245,245,245,1) 100%);
          border: rgb(229, 229, 229) 1px solid;
        }
        #controls {
          top: 10px;
          left: 110px;
          width: 360px;
          height: 45px;
        }
        #data-box {
          top: 10px;
          left: 500px;
          height: 45px;
          line-height: 45px;
          display: none;
        }
        #census-variable {
          width: 360px;
          height: 20px;
        }
        #legend { display: flex; display: -webkit-box; padding-top: 7px }
        .color-key {
          background: linear-gradient(to right,
            hsl(5, 69%, 54%) 0%,
            hsl(29, 71%, 51%) 17%,
            hsl(54, 74%, 47%) 33%,
            hsl(78, 76%, 44%) 50%,
            hsl(102, 78%, 41%) 67%,
            hsl(127, 81%, 37%) 83%,
            hsl(151, 83%, 34%) 100%);
          flex: 1;
          -webkit-box-flex: 1;
          margin: 0 5px;
          text-align: left;
          font-size: 1.0em;
          line-height: 1.0em;
        }
        #data-value { font-size: 2.0em; font-weight: bold }
        #data-label { font-size: 2.0em; font-weight: normal; padding-right: 10px; }
        #data-label:after { content: ':' }
        #data-caret { margin-left: -5px; display: none; font-size: 14px; width: 14px}
    </style>
  </head>
  <body>
    <div id="controls" class="nicebox">
      <div>
      <select id="census-variable">
        <option value="test">Fertility rate 2015</option>
        <option value="https://storage.googleapis.com/mapsdevsite/json/DP05_0017E">Median age</option>
      </select>
      </div>
      <div id="legend">
        <div id="census-min">min</div>
        <div class="color-key"><span id="data-caret">&#x25c6;</span></div>
        <div id="census-max">max</div>
      </div>
    </div>
    <div id="data-box" class="nicebox">
      <label id="data-label" for="data-value"></label>
      <span id="data-value"></span>
    </div>
    <div id="map"></div>
    <script>
      var mapStyle = [{
        'stylers': [{'visibility': 'off'}]
      }, {
        'featureType': 'landscape',
        'elementType': 'geometry',
        'stylers': [{'visibility': 'on'}, {'color': '#fcfcfc'}]
      }, {
        'featureType': 'water',
        'elementType': 'geometry',
        'stylers': [{'visibility': 'on'}, {'color': '#bfd4ff'}]
      }];
      var map;
      var censusMin = Number.MAX_VALUE, censusMax = -Number.MAX_VALUE;

      function initMap() {

        // load the map
        map = new google.maps.Map(document.getElementById('map'), {
          center: {lat: 40, lng: -100},
          zoom: 4,
          styles: mapStyle
        });


        // set up the style rules and events for google.maps.Data
        map.data.setStyle(styleFeature);
        map.data.addListener('mouseover', mouseInToRegion);
        map.data.addListener('mouseout', mouseOutOfRegion);

        // wire up the button
        var selectBox = document.getElementById('census-variable');
        google.maps.event.addDomListener(selectBox, 'change', function() {
          clearCensusData();
          loadCensusData(selectBox.options[selectBox.selectedIndex].value);
        });

        // state polygons only need to be loaded once, do them now
        loadMapShapes();

      }

      /** Loads the state boundary polygons from a GeoJSON source. */
      function loadMapShapes() {
        // load US state outline polygons from a GeoJson file
        map.data.loadGeoJson('region.geojson', { idPropertyName: 'meso:name_local' });

        // wait for the request to complete by listening for the first feature to be
        // added
        google.maps.event.addListenerOnce(map.data, 'addfeature', function() {
          google.maps.event.trigger(document.getElementById('census-variable'),
              'change');
        });
      }

      /**
       * Loads the census data from a simulated API call to the US Census API.
       *
       * @param {string} variable
       */
      function loadCensusData(variable) {
        // load the requested variable from the census API (using local copies)
        var xhr = new XMLHttpRequest();
        xhr.open('GET', variable + '.json');
        xhr.onload = function() {
          var censusData = JSON.parse(xhr.responseText);
          censusData.shift(); // the first row contains column names
          censusData.forEach(function(row) {
            var censusVariable = parseFloat(row[0]);
            var stateId = row[1];
            console.log('StateId row[0] '+censusVariable);
            console.log('censusVariable row[1] '+stateId);

            // keep track of min and max values
            if (censusVariable < censusMin) {
              censusMin = censusVariable;
            }
            if (censusVariable > censusMax) {
              censusMax = censusVariable;
            }

            // update the existing row with the new data
            map.data
              .getFeatureById(stateId)
              .setProperty('census_variable');
          });

          // update and display the legend
          document.getElementById('census-min').textContent =
              censusMin.toLocaleString();
          document.getElementById('census-max').textContent =
              censusMax.toLocaleString();
        };
        xhr.send();
      }

      /** Removes census data from each shape on the map and resets the UI. */
      function clearCensusData() {
        censusMin = Number.MAX_VALUE;
        censusMax = -Number.MAX_VALUE;
        map.data.forEach(function(row) {
          row.setProperty('census_variable', undefined);
        });
        document.getElementById('data-box').style.display = 'none';
        document.getElementById('data-caret').style.display = 'none';
      }

      /**
       * Applies a gradient style based on the 'census_variable' column.
       * This is the callback passed to data.setStyle() and is called for each row in
       * the data set.  Check out the docs for Data.StylingFunction.
       *
       * @param {google.maps.Data.Feature} feature
       */
      function styleFeature(feature) {
        var low = [5, 69, 54];  // color of smallest datum
        var high = [151, 83, 34];   // color of largest datum

        // delta represents where the value sits between the min and max
        var delta = (feature.getProperty('census_variable') - censusMin) /
            (censusMax - censusMin);

        var color = [];
        for (var i = 0; i < 3; i++) {
          // calculate an integer color based on the delta
          color[i] = (high[i] - low[i]) * delta + low[i];
        }

        // determine whether to show this shape or not
        var showRow = true;
        if (feature.getProperty('census_variable') == null ||
            isNaN(feature.getProperty('census_variable'))) {
          showRow = false;
        }

        var outlineWeight = 0.5, zIndex = 1;
        if (feature.getProperty('state') === 'hover') {
          outlineWeight = zIndex = 2;
        }

        return {
          strokeWeight: outlineWeight,
          strokeColor: '#fff',
          zIndex: zIndex,
          fillColor: 'hsl(' + color[0] + ',' + color[1] + '%,' + color[2] + '%)',
          fillOpacity: 0.75,
          visible: showRow
        };
      }

      /**
       * Responds to the mouse-in event on a map shape (state).
       *
       * @param {?google.maps.MouseEvent} e
       */
      function mouseInToRegion(e) {
        // set the hover state so the setStyle function can change the border
        e.feature.setProperty('state', 'hover');

        var percent = (e.feature.getProperty('census_variable') - censusMin) /
            (censusMax - censusMin) * 100;

        // update the label
        document.getElementById('data-label').textContent =
            e.feature.getProperty('NAME');
        document.getElementById('data-value').textContent =
            e.feature.getProperty('census_variable').toLocaleString();
        document.getElementById('data-box').style.display = 'block';
        document.getElementById('data-caret').style.display = 'block';
        document.getElementById('data-caret').style.paddingLeft = percent + '%';
      }

      /**
       * Responds to the mouse-out event on a map shape (state).
       *
       * @param {?google.maps.MouseEvent} e
       */
      function mouseOutOfRegion(e) {
        // reset the hover state, returning the border to normal
        e.feature.setProperty('state', 'normal');
      }

    </script>
    <script async defer
        src="https://maps.googleapis.com/maps/api/js?key=API_KEY&callback=initMap">
    </script>
  </body>
</html>

这是我的人口普查数据（test.json）的JSON文件：

[["DP02_0066PE","region"],
["2.31", "Adana"],
["2.86", "Adıyaman"],
["2.06", "Afyonkarahisar"],
["3.80", "Ağrı"],
["2.24", "Aksaray"],
["1.79", "Amasya"],
["1.76", "Ankara"],
["1.96", "Antalya"],
["2.15", "Ardahan"],
["1.73", "Artvin"],
["1.85", "Aydın"],
["1.64", "Balıkesir"],
["1.58", "Bartın"],
["3.24", "Batman"],
["2.07", "Bayburt"],
["1.71", "Bilecik"],
["2.42", "Bingöl"],
["3.40", "Bitlis"],
["1.59", "Bolu"],
["1.77", "Burdur"],
["1.91", "Bursa"],
["1.53", "Çanakkale"],
["1.77", "Çankırı"],
["1.83", "Çorum"],
["1.84", "Denizli"],
["3.21", "Diyarbakır"],
["1.85", "Düzce"],
["1.53", "Edirne"],
["1.97", "Elazığ"],
["1.82", "Erzincan"],
["2.51", "Erzurum"],
["1.55", "Eskişehir"],
["3.15", "Gaziantep"],
["1.62", "Giresun"],
["1.66", "Gümüşhane"],
["2.69", "Hakkâri"],
["2.70", "Hatay"],
["3.04", "Iğdır"],
["1.70", "Isparta"],
["1.88", "İstanbul"],
["1.72", "İzmir"],
["2.61", "Kahramanmaraş"],
["1.56", "Karabük"],
["2.10", "Karaman"],
["2.64", "Kars"],
["1.62", "Kastamonu"],
["2.18", "Kayseri"],
["2.92", "Kilis"],
["1.71", "Kırıkkale"],
["1.54", "Kırklareli"],
["1.79", "Kırşehir"],
["2.06", "Kocaeli"],
["2.18", "Konya"],
["1.58", "Kütahya"],
["2.01", "Malatya"],
["1.92", "Manisa"],
["3.41", "Mardin"],
["2.15", "Mersin"],
["1.75", "Muğla"],
["3.45", "Muş"],
["1.96", "Nevşehir"],
["2.18", "Niğde"],
["1.81", "Ordu"],
["2.47", "Osmaniye"],
["1.78", "Rize"],
["1.92", "Sakarya"],
["1.80", "Samsun"],
["4.38", "Şanlıurfa"],
["3.55", "Siirt"],
["1.72", "Sinop"],
["4.01", "Şırnak"],
["1.96", "Sivas"],
["1.93", "Tekirdağ"],
["1.72", "Tokat"],
["1.85", "Trabzon"],
["1.69", "Tunceli"],
["1.73", "Uşak"],
["3.36", "Van"],
["1.77", "Yalova"],
["1.99", "Yozgat"],
["1.55", "Zonguldak"]]

包含所有geoJSON数据的另一个文件太大了，无法在此处发布。但如果有必要，我可以找到一种方法与你分享。

Answer 1

我终于明白了。坦率地说，这是我犯下的一个非常愚蠢的错误。我想我已经累了，没有意识到我的错误，所以我要感谢所有评论我问题的人，因为它帮助我意识到我做错了什么。

有两个JSON文件。一个包含坐标，我们称之为 coordinates.geojson ，另一个包含人口普查数据，我们称之为 census.json

现在让这些代码行工作，

map.data .getFeatureById(stateId) .setProperty('census_variable');

您必须确保 stateId 对应 census.json 文件中的ID以及 coordinates.geojson 文件。

在我的情况下， census.json 文件中的stateId不等于 coordinates.geojson 中的第一个ID /状态这是Aydin。而 census.json 从Adana开始，然后是Adıyaman等。

因此，我必须将人口普查数据的顺序更改为

[["DP02_0066PE","region"],
["1.85", "Aydin"],
["1.72", "Izmir"],
["1.64", "Balikesir"],
["1.53", "Çanakkale"],
["1.53", "Edirne"],
["1.54", "Kirklareli"],
["1.93", "Tekirdag"],
["1.71", "Bilecik"],
["1.91", "Bursa"],
["1.88", "Istanbul"],
["2.06", "Kocaeli"],
["1.92", "Sakarya"],
["1.59", "Bolu"],
["1.55", "Eskisehir"],
["1.62", "Kastamonu"],
["1.96", "Antalya"],
["2.06", "Afyon"],
["1.77", "Burdur"],
["1.84", "Denizli"],
["1.70", "Isparta"],
["1.58", "Kütahya"],
["1.92", "Manisa"],
["1.75", "Mugla"],
["2.86", "Adiyaman"],
["1.97", "Elazig"],
["2.61", "Kahramanmaras"],
["2.01", "Malatya"],
["2.15", "Içel"],
["1.79", "Kirsehir"],
["2.18", "Kayseri"],
["1.96", "Nevsehir"],
["2.70", "Hatay"],
["1.79", "Amasya"],
["1.83", "Çorum"],
["1.62", "Giresun"],
["1.81", "Ordu"],
["1.72", "Sinop"],
["1.96", "Sivas"],
["1.80", "Samsun"],
["1.72", "Tokat"],
["1.73", "Artvin"],
["2.51", "Erzurum"],
["1.82", "Erzincan"],
["1.78", "Rize"],
["1.85", "Trabzon"],
["3.80", "Agri"],
["2.42", "Bingöl"],
["3.21", "Diyarbakir"],
["3.45", "Mus"],
["3.40", "Bitlis"],
["1.76", "Ankara"],
["1.77", "Çankiri"],
["1.55", "Zonguldak"],
["2.18", "Konya"],
["2.10", "Karaman"],
["1.73", "Usak"],
["3.15", "Gaziantep"],
["4.38", "Sanliurfa"],
["2.31", "Adana"],
["1.71", "Kirikkale"],
["2.18", "Nigde"],
["2.24", "Aksaray"],
["1.99", "Yozgat"],
["1.66", "Gümüshane"],
["2.07", "Bayburt"],
["2.64", "Kars"],
["3.41", "Mardin"],
["3.24", "Batman"],
["3.55", "Siirt"],
["4.01", "Sirnak"],
["1.69", "Tunceli"],
["2.69", "Hakkari"],
["3.36", "Van"],
["2.15", "Ardahan"],
["3.04", "Igdir"],
["2.92", "Kilis"],
["2.47", "Osmaniye"],
["1.77", "Yalova"],
["1.85", "Düzce"],
["1.56", "Karabük"],
["1.58", "Bartin"]]

最后但并非最不重要的是，请注意我删除了所有特定的土耳其字符，例如ğ，ı和ş因为来自 coordinates.geojson 的ID，其中拼写没有它们。因此，我将Ağrı改为Agri，等等。

我想如果我使用数字作为ID而不是名字会更好。

我希望这会阻止其他人犯同样的错误。

未捕获的TypeError：无法读取未定义的属性'setProperty'

1 个答案: