Fatal编程技术网
  • javascript/
  • Javascript 未捕获类型错误：无法读取属性'；setProperty'；未定义的

Javascript 未捕获类型错误：无法读取属性'；setProperty'；未定义的

javascript json google-maps google-maps-api-3

Javascript 未捕获类型错误：无法读取属性'；setProperty'；未定义的,javascript,json,google-maps,google-maps-api-3,Javascript,Json,Google Maps,Google Maps Api 3,我试图在互联网上找到这个问题的答案。我找到了一个，但似乎没有人能给出正确的答案 我正在尝试谷歌地图API网站上的一个例子。为了使用不同国家的人口普查数据，我只对您的代码做了一些更改 我更改了链接，以便它可以访问我自己的json文件。在region.geojson中，您拥有土耳其各省的所有坐标；在test.json中，您拥有每个省份的人口普查数据 我将普查数据放在相同的格式中，但当loadCensusData函数点击时 地图数据 .getFeatureById（stateId） .setPrope

我试图在互联网上找到这个问题的答案。我找到了一个，但似乎没有人能给出正确的答案

  • 我正在尝试谷歌地图API网站上的一个例子。为了使用不同国家的人口普查数据，我只对您的代码做了一些更改
  • 我更改了链接，以便它可以访问我自己的json文件。在region.geojson中，您拥有土耳其各省的所有坐标；在test.json中，您拥有每个省份的人口普查数据
  • 我将普查数据放在相同的格式中，但当loadCensusData函数点击时
    地图数据 .getFeatureById（stateId） .setProperty（“普查变量”，普查变量） 迭代时，它会给我以下错误，“UncaughtTypeError:无法读取未定义的属性'setProperty'。 如果我对此进行注释，它将继续迭代直到结束，但问题是我将无法使用“census_variable”，因为它尚未设置。 4.如果我改变链接指向美国人口普查数据，它会像预期的那样再次发挥作用

    有没有办法解决这个错误？或者你知道这是什么原因吗

    请参见下面我的地图代码：

    <!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>
    另一个包含所有geoJSON数据的文件太大，无法在这里发布。但如果有必要，我可以找到一种方法与您分享。

    我终于找到了答案。坦率地说，这是我犯的一个相当愚蠢的错误。我想我已经很累了，没有意识到我的错误，所以我要感谢所有对我的问题发表评论的人，因为这帮助我意识到我做错了什么

    有两个JSON文件。一个包含坐标，我们称之为坐标.geojson，另一个包含普查数据，我们称之为普查.json

    现在让这些代码行开始工作

    map.data
     .getFeatureById(stateId)
     .setProperty('census_variable');
    您必须确保stateId与普查.json文件中的id以及坐标.geojson文件中的id都对应

    在我的例子中，census.json文件中的stateId不等于coordinates.geojson中的第一个id/state，它是Aydin。然而，census.json是从Adana开始的，然后是Adıyaman等

    因此，我不得不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一点是，请注意，我删除了所有特定的土耳其字符，如ğ、ı和ş，因为id来自坐标.geojson，其中没有它们。因此，我将Ağrı改为Agri等等

    我想如果我用数字作为ID而不是名字会更好

    我希望这将防止其他人犯同样的错误。

    您的问题是这些函数中没有检查空值的错误。然而，可能还有更多。只需确保传递给函数的对象具有正在更改的属性。
    map.data.getFeatureById（stateId）
    正在返回未定义的属性可能
    stateId
    不是JSON文件中的id。 
    [["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"]]