从文本区域在谷歌地图上绘制 kml 图层

Question

我想用 javascript api 在谷歌地图上绘制一个 kml 图层，将 kml 代码复制到 textarea 中，就像他们在此页面中所做的那样：

http://display-kml.appspot.com/

我在文档中找到的所有示例都是从文件中加载 kml 层；

Answer 1

Example。使用 geoxml3 第三方 KML 解析器和另一个第三方库，增加了编辑 KML 的能力（听起来你不需要）。

working fiddle

代码sn-p：

var geocoder;
var map;

function initialize() {
  map = new google.maps.Map(
    document.getElementById("map_canvas"), {
      center: new google.maps.LatLng(37.4419, -122.1419),
      zoom: 13,
      mapTypeId: google.maps.MapTypeId.ROADMAP
    });
  document.getElementById("kmlString").value = '<kml><Document><Placemark id="Tester"><styleUrl>#transYellowPolyActive</styleUrl><name>Tester</name><Polygon><outerBoundaryIs><LinearRing><tessellate>0</tessellate><coordinates>6.30889892578125,53.28820543193896 6.29791259765625,53.28410053532493 6.233367919921875,53.21096737507053 6.5093994140625,53.19698389904798 6.50390625,53.27096221595853</coordinates></LinearRing></outerBoundaryIs></Polygon></Placemark><Placemark id="jahoor"><styleUrl>#transYellowPolyActive</styleUrl><name>jahoor</name><Polygon><outerBoundaryIs><LinearRing><tessellate>0</tessellate><coordinates>6.168479919433594,53.30318495818702 6.143760681152344,53.29579845109269 6.138267517089844,53.27281003615208 6.195259094238281,53.2707568976735 6.2010955810546875,53.29867113343524</coordinates></LinearRing></outerBoundaryIs></Polygon></Placemark></Document></kml>';
}
google.maps.event.addDomListener(window, "load", initialize);

var mapOverlays = [];
var geoXml = null;
//create a common infoWindow object
var infWindow = new google.maps.InfoWindow();

function setMapFromKML(kmlString) {
  if (kmlString.length == 0) {
    return false;
  }
  if (typeof geoXML3 == "undefined") { // check for include of geoxml3 parser
    // http://code.google.com/p/geoxml3/ 
    alert("geoxml3.js not included");
    return;
  }
  if (!geoXml)
    geoXml = new geoXML3.parser({
      map: map,
      zoom: false,
      suppressInfoWindows: true
    });

  geoXml.parseKmlString(kmlString);

  var tmpOverlay, ovrOptions;
  for (var m = 0; m < geoXml.docs[0].placemarks.length; m++) {
    if (geoXml.docs[0].placemarks[m].Polygon) {

      tmpOverlay = geoXml.docs[0].placemarks[m].polygon;
      tmpOverlay.type = "polygon";
    } else if (geoXml.docs[0].placemarks[m].LineString) {

      tmpOverlay = geoXml.docs[0].placemarks[m].polyline;
      tmpOverlay.type = "polyline";
    } else if (geoXml.docs[0].placemarks[m].Point) {

      tmpOverlay = geoXml.docs[0].placemarks[m].marker;
      tmpOverlay.type = "marker";
    }

    if (geoXml.docs[0].placemarks[m].name) {
      tmpOverlay.title = geoXml.docs[0].placemarks[m].name;
    } else {
      tmpOverlay.title = "";
    }

    if (geoXml.docs[0].placemarks[m].description) {
      tmpOverlay.content = geoXml.docs[0].placemarks[m].description;
    } else {
      tmpOverlay.content = "";
    }

    //attach the click listener to the overlay
    AttachClickListener(tmpOverlay);

    //save the overlay in the array
    mapOverlays.push(tmpOverlay);
  }
  map.fitBounds(geoXml.docs[0].bounds);
}

function AttachClickListener(overlay) {
  google.maps.event.addListener(overlay, "click", function(clkEvent) {
    var infContent = GetContent(overlay);
    openInfowindow(overlay, clkEvent.latLng, infContent);
  });
}

function GetContent(overlay) {
  var content = '<div><h3>' + overlay.title + '</h3>' + overlay.content + '<br></div>';
  return content;
}

function openInfowindow(overlay, latLng, content) {
  var div = document.createElement('div');
  div.innerHTML = content;
  setStyle(div, {
    height: "100%"
  });
  infWindow.setContent(div);
  infWindow.setPosition(latLng);
  infWindow.relatedOverlay = overlay;
  var t = overlay.get('fillColor');
  infWindow.open(mapObj);
}

html,
body,
#map_canvas {
  height: 500px;
  width: 500px;
  margin: 0px;
  padding: 0px
}

<script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk&libraries=drawing,geometry"></script>
<script src="https://cdn.rawgit.com/geocodezip/geoxml3/master/polys/geoxml3.js"></script>
<script src="https://cdn.rawgit.com/geocodezip/geoxml3/master/ProjectedOverlay.js"></script>

<div id="map_canvas" style="border: 2px solid #3872ac;"></div>
<input type="button" value="parse KML to map" onclick="setMapFromKML(document.getElementById('kmlString').value)" />
<textarea id="kmlString" style="width:100%; height:500px"></textarea>

Answer 2

另一种方法是将 kml 转换为 GeoJSON 并使用数据层，而不是使用 Mapbox 的 toGeoJSON library。您获得的优势是Google Maps Data Layer. 的功能更多

不过，这样做的缺点是 toGeoJSON 不支持 kmz 格式，您需要先提取文件。 我已经修改了使用 toGeoJSON 的 geocodezip 的小提琴。我不得不更改 kml 多边形，因为如果多边形没有关闭，则 toGeoJSON 将不起作用，它在多边形中具有相同的坐标和最后一个坐标。

您可以查看代码Fiddle here。

//create a common infoWindow object
var infWindow = new google.maps.InfoWindow();

function setMapFromKML(kmlString) {
  if (kmlString.length == 0) {
    return false;
  }
  if (typeof toGeoJSON == "undefined") { // check for include of togeojson parser
    // https://github.com/mapbox/togeojson
    alert("toGeoJSON.js not included");
    return;
  }
  //convert dom string to xmldocument 
  var domparser = new DOMParser();
  var kml = domparser.parseFromString(kmlString, "text/xml");

  var geojson = toGeoJSON.kml(kml);

  var features = map.data.addGeoJson(geojson);

  //save the overlay in the array

  var bounds = new google.maps.LatLngBounds();

  features.forEach(function(feature) {


    feature.getGeometry().forEachLatLng(function(latlng) {
      bounds.extend(latlng);
    });


  });

  map.fitBounds(bounds);

  map.data.addListener('click', function(event) {
    var infContent = GetContent(event);
    var latlng;
    if (typeof event.feature.getGeometry().get !== "undefined") { //for point
      latlng = event.feature.getGeometry().get();
    } else { //polygon/multi,etc...
      var polybounds = new google.maps.LatLngBounds()
      event.feature.getGeometry().forEachLatLng(function(featurelatlng) {
        polybounds.extend(featurelatlng);
      });

      latlng = polybounds.getCenter();
    }


    openInfowindow(latlng, infContent);

  });



}

function GetContent(event) {


  var content = '<div><h3>' + event.feature.getProperty('name') + '</h3>' + event.feature.getGeometry().
  getType() + '<br></div>';
  return content;
}

function openInfowindow(latLng, content) {
  var div = document.createElement('div');
  div.innerHTML = content;

  infWindow.setContent(div);
  infWindow.setPosition(latLng);
  infWindow.open(map);
}