Determine center/bounding box of FusionTablesLayer in Google Maps API

问题

is there any way I can determine central point of FusionTablesLayer? I was thinking about using some event to handle the layer rendering but without any luck.

Thanks!

回答1:

The following code shows how to retrieve data from a Fusion Table using the Chart Tools API, then use that data to fit the bounds of the map to the data in the Fusion Table. This will hopefully give you some ideas for how to find the center!

<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="content-type" content="text/html; charset=UTF-8"/>

    <style type="text/css">
      body { height: 100%; margin: 0px; padding: 10px; }
      #map-canvas { height: 600px; width: 700px; }
    </style>

    <script type="text/javascript"
        src="http://maps.google.com/maps/api/js?sensor=false"></script>
    <script type="text/javascript" src="http://www.google.com/jsapi"></script>

    <script>
      google.load('visualization', '1');

      function initialize() {
        var queryText = encodeURIComponent(
            "SELECT Latitude,Longitude FROM 345328");
        var query = new google.visualization.Query(
            'http://www.google.com/fusiontables/gvizdata?tq='  + queryText);

        query.send(function(response) {
          var numRows = response.getDataTable().getNumberOfRows();

          //create the list of lat/long coordinates
          var coordinates = [];
          for(i = 0; i < numRows; i++) {
            var lat = response.getDataTable().getValue(i, 0);
            var lng = response.getDataTable().getValue(i, 1);
            coordinates.push(new google.maps.LatLng(lat, lng));
          }  

          var map = new google.maps.Map(document.getElementById('map-canvas'), {
            mapTypeId: google.maps.MapTypeId.ROADMAP
          });
          var bounds = new google.maps.LatLngBounds();
          for (var i = 0; i < coordinates.length; i++) {
            bounds.extend(coordinates[i]);
          }
          map.fitBounds(bounds);

          var layer = new google.maps.FusionTablesLayer({
            query: {
              select: 'Latitude',
              from: 345328
            }
          });
          layer.setMap(map);
        });
      }
      google.maps.event.addDomListener(window, 'load', initialize);
    </script>

  </head>
  <body>
    <div id="map-canvas"></div>
  </body>
</html>

来源：https://stackoverflow.com/questions/8434685/determine-center-bounding-box-of-fusiontableslayer-in-google-maps-api

标签

google-maps

google-maps-api-3

google-fusion-tables