计算中心的经纬度坐标

I'm looking for a elegant solution that calculates the center between several latitude-longitude /questions/tagged/latitude-longitude coordinates (for example, to simply center a map to the center of a google-maps polygon).

Table: locations:

id |    city    |   latitude   |  longitude
-----------------------------------------------
1  |   Berlin   |   52.524268  |   13.406290
-----------------------------------------------
2  |   London   |   51.508129  |  -0.1280050    
-----------------------------------------------
3  |   Hamburg  |   53.551084  |   9.9936817
-----------------------------------------------
4  |  Amsterdam |   52.370215  |   4.8951678
-----------------------------------------------

目前的计算：

function calculateCenter($array_locations) {

    $minlat = false;
    $minlng = false;
    $maxlat = false;
    $maxlng = false;

    foreach ($array_locations as $geolocation) {

         if ($minlat === false) { $minlat = $geolocation['lat']; } else { $minlat = ($geolocation['lat'] < $minlat) ? $geolocation['lat'] : $minlat; }
         if ($maxlat === false) { $maxlat = $geolocation['lat']; } else { $maxlat = ($geolocation['lat'] > $maxlat) ? $geolocation['lat'] : $maxlat; }
         if ($minlng === false) { $minlng = $geolocation['lon']; } else { $minlng = ($geolocation['lon'] < $minlng) ? $geolocation['lon'] : $minlng; }
         if ($maxlng === false) { $maxlng = $geolocation['lon']; } else { $maxlng = ($geolocation['lon'] > $maxlng) ? $geolocation['lon'] : $maxlng; }
    }

    // Calculate the center
    $lat = $maxlat - (($maxlat - $minlat) / 2);
    $lon = $maxlng - (($maxlng - $minlng) / 2);

    return array($lat, $lon);
}

当您使用 Google 地图时，您可以使用获取边界() https://developers.google.com/maps/documentation/javascript/reference#Map方法和获取中心() https://developers.google.com/maps/documentation/javascript/reference#LatLngBounds method.

我重新排列了你的坐标以形成一个凸多边形（所有顶点都指向“向外”，远离中心）。通过将第一个坐标作为第一个和最后一个值来闭合多边形polygonCoords array.

See jsfiddle http://jsfiddle.net/k4Q4K/1/

var map; 
var polygon;
var bounds = new google.maps.LatLngBounds();
var i; 
var myLatLng = new google.maps.LatLng(52.5,6.6);
var myOptions = {
  zoom: 5,
  center: myLatLng,
  mapTypeId: google.maps.MapTypeId.TERRAIN
};
map = new google.maps.Map(document.getElementById("map_canvas"),
    myOptions);

var polygonCoords = [
    new google.maps.LatLng(52.524268,13.406290),
    new google.maps.LatLng(53.551084,9.9936817),
    new google.maps.LatLng(51.508129,-0.1280050),
    new google.maps.LatLng(52.370215,4.8951678),
    new google.maps.LatLng(52.524268,13.406290)//Start & end point 
    ];

polygon = new google.maps.Polygon({
   paths: polygonCoords,
   strokeColor: "#FF0000",
   strokeOpacity: 0.8,
   strokeWeight: 3,
   fillColor: "#FF0000",
   fillOpacity: 0.05
 });
 polygon.setMap(map);

for (i = 0; i < polygonCoords.length; i++) {
   bounds.extend(polygonCoords[i]);
}

// The Center of the polygon
var latlng = bounds.getCenter();

var marker = new google.maps.Marker({
  position: latlng, 
  map: map, 
  title:latlng.toString()
});