我是OpenLayers的新手，我正在尝试将KML图层添加到地图中。
这是我的脚本：
var projection = ol.proj.get('EPSG:3857');
var mapa = new ol.layer.Tile({
source: new ol.source.OSM()
});
var map = new ol.Map({
target: 'map',
controls: ol.control.defaults({
attributionOptions: /** @type {olx.control.AttributionOptions} */ ({
collapsible: false
})
}),
view: new ol.View({
center: [-5462834.47, -3058929.70],
projection: projection,
zoom: 10
})
});
map.addLayer(mapa);
var alfalfa_zaragoza = new ol.layer.Vector({
source: new ol.source.Vector({
url: 'kml/ms_alfalfazaragoza_rgba_ndvi.kml',
format: new ol.format.KML()
}),
extractStyles: true,
extractAttributes: true,
maxDepth: 2,
setVisibility: true
});
document.getElementById('addKML').onclick = function () {
map.addLayer(alfalfa_zaragoza);
};
我的html页面：
<html>
<head>
<title>Title</title>
<link rel="stylesheet" href="http://openlayers.org/en/v3.2.0/css/ol.css" type="text/css">
<script type="javascript" src="<%=request.getContextPath()%>/resources/OpenLayersv3.14.2/build/ol.js"></script>
<script src="http://maps.google.com/maps/api/js?v=3&sensor=false"></script>
<link rel="stylesheet" href="<%=request.getContextPath()%>/resources/OpenLayersv3.14.2/css/ol.css" type="text/css" />
<link rel="stylesheet" href="<%=request.getContextPath()%>/resources/ol3-google-maps-v0.4/ol3gm.css" type="text/css" />
<link rel="stylesheet" href="<%=request.getContextPath()%>/resources/layout.css" type="text/css" />
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css" />
</head>
<body>
<div class="container-fluid">
<div class="row-fluid">
<div class="span12">
<div id="map" class="map"></div>
</div>
</div>
<div class="row-fluid">
<div class="span12">
<h4>Concept example</h4>
<div class="row">
<div class="col-md-4 col-sm-4">
<fieldset>
<input id="addKML" type="button" value="Add KML"
title="Add KML layer"/>
</fieldset>
</div>
</div>
</div>
</div>
</div>
<script src="<%=request.getContextPath()%>/resources/ol3-google-maps-v0.4/ol3gm.js"></script>
<script src="<%=request.getContextPath()%>/resources/kml.js"></script>
</body>
</html>
错误在哪里？想法是按“addKML”按钮，图层被添加到地图中，但是当我按下它时，没有任何反应。
你只需忘记这行中的“新”：
var projection = ol.proj.get('EPSG:3857');
替换为这个正确的：
var projection = new ol.proj.get('EPSG:3857');