Is there any way to see when several placemarks superimposed on the same positions?

问题

Is there any way to see when several placemarks superimposed on the same positions?

As the figure below, Google Earth, we have a way to see it. Thank you.

回答1:

Yes, you can use your imagination and make a custom cluster. See this plunker demo, I use the following function to create a cluster like:

var displayOverlapping = function(pixel) {

  var f = map.forEachFeatureAtPixel(pixel, function(ft, l) {
      return ft;
  });
  if (f && f.get('type') == 'cluster') {

    if(f.get('expanded') === true) return;

    var geom = f.getGeometry(),
        coord = geom.getCoordinates(),
        px = map.getPixelFromCoordinate(coord),
        extent = [coord[0], coord[1], coord[0], coord[1]],
        ar_features = [];

    sourceFeatures.forEachFeatureInExtent(extent, function(ft){
        if(ft.get('type') == 'click') ar_features.push(ft);
    });
    var angle = (100 / ar_features.length) * 3.6;

    f.set('expanded', true);
    f.setStyle(style_cluster_hover);
    multiLineString.setCoordinates([]);

    ar_features.forEach(function(row, index){
      var angle2 = index * angle,
          px_end = rotate(px[0], px[1], angle2, 30),
          cd_end = map.getCoordinateFromPixel(px_end);

      multiLineString.appendLineString(
          new ol.geom.LineString([coord, cd_end])
      );

      row.setGeometry(new ol.geom.Point(cd_end));
      row.setStyle(style_parada);
    });
  }
};

The function is triggered on pointermove event.

来源：https://stackoverflow.com/questions/35866107/is-there-any-way-to-see-when-several-placemarks-superimposed-on-the-same-positio