maptalks - VectorLayer: Filter geometries by property condition

VectorLayer: Filter geometries by property condition

index.html

<!DOCTYPE html>
<html>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Layer - VectorLayer: Filter geometries by property condition</title>
  <style type="text/css">
    html,body{margin:0px;height:100%;width:100%}
    .container{width:100%;height:100%}
    .pane{background:#34495e;line-height:28px;color:#fff;z-index:10;position:absolute;top:20px;right:20px}
    .pane a{display:block;color:#fff;text-align:left;padding:0 10px;min-width:28px;min-height:28px;float:left}
  </style>
  <link rel="stylesheet" href="https://unpkg.com/maptalks/dist/maptalks.css">
  <script type="text/javascript" src="https://unpkg.com/maptalks/dist/maptalks.min.js"></script>
  <body>

    <div id="map" class="container"></div>
    <div class="pane"><a href="javascript:filter();">Select >= 200</a></div>

    <script>
      var map = new maptalks.Map('map', {
        center: [-0.113049,51.498568],
        zoom: 14,
        baseLayer: new maptalks.TileLayer('base', {
          urlTemplate: 'https://{s}.basemaps.cartocdn.com/light_all/{z}/{x}/{y}.png',
          subdomains: ["a","b","c","d"],
          attribution: '&copy; <a href="http://osm.org">OpenStreetMap</a> contributors, &copy; <a href="https://carto.com/">CARTO</a>'
        }),
        layers : [
          new maptalks.VectorLayer('v')
        ]
      });

      var layer = map.getLayer('v');

      // select features and update symbol
      function filter() {
        layer.filter(['>=', 'count', 200])
          .forEach(function (feature) {
            feature.updateSymbol([
              {
                'polygonFill': 'rgb(216,115,149)'
              }
            ]);
          });
      }

      //prepare data
      for (var i = 0; i < 3; i++) {
        new maptalks.Polygon([
          [-0.123049 + 0.02 * i, 51.503568],
          [-0.136049 + 0.02 * i, 51.503568],
          [-0.136049 + 0.02 * i, 51.488568],
          [-0.123049 + 0.02 * i, 51.488568]
        ], {
          'properties': {
            'count': (i + 1) * 100
          },
          'symbol': [
            {
              'polygonFill': '#747474',
              'polygonOpacity': 0.5,
              'lineColor': '#000',
              'lineWidth': 2
            },
            {
              'textName' : '{count}',
              'textSize' : 40,
              'textFill' : '#fff'
            }
          ]
        }).addTo(layer);
      }

    </script>
  </body>
</html>

var map = new maptalks.Map('map', {
  center: [-0.113049, 51.498568],
  zoom: 14,
  baseLayer: new maptalks.TileLayer('base', {
    urlTemplate: 'https://{s}.basemaps.cartocdn.com/light_all/{z}/{x}/{y}.png',
    subdomains: ["a", "b", "c", "d"],
    attribution: '© <a href="http://osm.org">OpenStreetMap</a>  contributors, © <a href="https://carto.com/">CARTO</a> '
  }),
  layers: [
    new maptalks.VectorLayer('v')
  ]
});

var layer = map.getLayer('v');

// select features and update symbol

function filter() {
  layer.filter(['>=', 'count', 200])
    .forEach(function(feature) {
      feature.updateSymbol([{
        'polygonFill': 'rgb(216,115,149)'
      }]);
    });
}

//prepare data
for (var i = 0; i < 3; i++) {
  new maptalks.Polygon([
    [-0.123049 + 0.02 * i, 51.503568],
    [-0.136049 + 0.02 * i, 51.503568],
    [-0.136049 + 0.02 * i, 51.488568],
    [-0.123049 + 0.02 * i, 51.488568]
  ], {
    'properties': {
      'count': (i + 1) * 100
    },
    'symbol': [{
      'polygonFill': '#747474',
      'polygonOpacity': 0.5,
      'lineColor': '#000',
      'lineWidth': 2
    }, {
      'textName': '{count}',
      'textSize': 40,
      'textFill': '#fff'
    }]
  }).addTo(layer);
}