如何使用kml图层查找地图区域？

Question

您好，我试图找到cm2的英亩面积。但是有可能找到kml层的区域吗？

          var ctaLayer = new google.maps.KmlLayer({
            url: 'http://mango.co.in/Images/5562-f63a29f2-6c44-4943-9709-973dd65f538a.kml'
          });
          ctaLayer.setMap(map);

Answer 1

使用KmlLayer找不到多边形的区域。 KmlLayer不提供对多边形的访问。如果您使用第三方解析器（例如geoxml3或geoxml-v3）将KML呈现为原生Google Maps Javascript API v3多边形，则可以使用geometry library来计算该区域。

proof of concept fiddle

代码段：

var geocoder;
var map;

function initialize() {
    map = new google.maps.Map(document.getElementById("map_canvas"));
    infowindow = new google.maps.InfoWindow({});
    geoXml = new geoXML3.parser({
        map: map,
        infoWindow: infowindow,
        singleInfoWindow: true,
        suppressInfoWindows: true,
        afterParse: useTheData
    });
    geoXml.parseKmlString(kmlData);
}
google.maps.event.addDomListener(window, "load", initialize);

function createClickablePolygon(polygon) {
    google.maps.event.addListener(polygon, 'click', function (evt) {
        infowindow.setPosition(polygon.bounds.getCenter());
        infowindow.setContent((google.maps.geometry.spherical.computeArea(polygon.getPath())/1000/1000).toFixed(2) + " sq km");
        infowindow.open(map);
    });

}

function useTheData(doc) {
    var currentBounds = map.getBounds();
    if (!currentBounds) currentBounds = new google.maps.LatLngBounds();
    // Geodata handling goes here, using JSON properties of the doc object
    sidebarHtml = '<table><tr><td><a href="javascript:showAll();">Show All</a></td></tr>';
    //  var sidebarHtml = '<table>';
    geoXmlDoc = doc[0];
    if (!geoXmlDoc || !geoXmlDoc.placemarks) return;
    for (var i = 0; i < geoXmlDoc.placemarks.length; i++) {
        // console.log(doc[0].markers[i].title);
        var placemark = geoXmlDoc.placemarks[i];
        if (placemark.polygon) {
            createClickablePolygon(placemark.polygon);
        }

    }
};


var kmlData = '<?xml version="1.0" encoding="utf-8"?><kml xmlns="http://earth.google.com/kml/2.2"><Document><Style id="Style1"><LineStyle><color>66000001</color><width>1</width></LineStyle><PolyStyle><color>66ff6633</color><fill>1</fill><outline>1</outline></PolyStyle></Style><Placemark id="Monday"><name>Monday</name><visibility>1</visibility><open>0</open><styleUrl>#Style1</styleUrl><Polygon><extrude>0</extrude><tessellate>1</tessellate><altitudeMode>clampToGround</altitudeMode><outerBoundaryIs><LinearRing><coordinates>-116.365673309192,43.6628960911185 -116.365591334179,43.6560111958534 -116.364375539124,43.6559975333512 -116.364402864128,43.6483204644173 -116.359539767727,43.6483955662698 -116.359567092732,43.64422573708 -116.356452545151,43.6442223004997 -116.356329582632,43.6403188481927 -116.355482675135,43.6384234484285 -116.354444492608,43.6376550793648 -116.354198567569,43.6375697515905 -116.354198567569,43.6375560890883 -116.354348855093,43.6375355534256 -116.352818906307,43.6375834140927 -116.349636046216,43.6375697515905 -116.349677033722,43.6339155770838 -116.317438473925,43.6339155770838 -116.314392238855,43.6339600011706 -116.314187301323,43.6484194546938 -116.334391040727,43.6484843306243 -116.33440470323,43.6627594660968 -116.335292598233,43.6629438679665 -116.336767980829,43.6629097536206 -116.359348576516,43.6629985179752 -116.360673587769,43.6628994438797 -116.365673309192,43.6628960911185</coordinates></LinearRing></outerBoundaryIs></Polygon></Placemark><Style id="Style2"><LineStyle><color>66333333</color><width>1</width></LineStyle><PolyStyle><color>66ff6633</color><fill>1</fill><outline>1</outline></PolyStyle></Style><Placemark id="Monday"><name>Monday</name><visibility>1</visibility><open>0</open><styleUrl>#Style2</styleUrl><Polygon><extrude>0</extrude><tessellate>1</tessellate><altitudeMode>clampToGround</altitudeMode><outerBoundaryIs><LinearRing><coordinates>-116.334445690736,43.6628618929535 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html, body, #map_canvas {
    height: 500px;
    width: 500px;
    margin: 0px;
    padding: 0px
}

<script src="https://maps.googleapis.com/maps/api/js?libraries=geometry"></script>
<script src="http://geoxml3.googlecode.com/svn/branches/polys/geoxml3.js"></script>
<div id="map_canvas" style="width:750px; height:450px; border: 2px solid #3872ac;"></div>