我正在尝试使用 OpenLayers 3 创建在线地图。
我对使用 OpenLayers 是全新的，我想做的就是获取我在地图上绘制的点、线、多边形的坐标。我知道有一个 featuresadded 参数可用，但我无法正确实现它。
有人能给我指明如何获取绘制特征的坐标（在alert() 或console.log 中）的正确方向吗？
万分感谢！！
这是我的代码：
<html>
<head>
<script src="http://openlayers.org/en/v3.3.0/build/ol.js" type="text/javascript"></script>
<link rel="stylesheet" href="ol.css" type="text/css">
<style type="text/css">
body {
font-family: Verdana, Geneva, Arial, Helvetica, sans-serif;
font-size: small;
}
#map {
clear: both;
position: relative;
border: 1px solid black;
}
#wrapper {
width: 337px;
height: 50px;
}
#location {
float: right;
font-family: Arial, Verdana, sans-serif;
font-size: 12px;
color: #483D8B;
background-color: white;
}
#nodelist{
font-family: Arial, Verdana, sans-serif;
font-size: 14px;
color: #000000;
font-style: normal;
background-color: white;
}
</style>
<script type="text/javascript">
var map;
var draw;
var transformed_coordinate;
var vector;
function init() {
var view = new ol.View({
center: ol.proj.transform([13.1929, 55.718],'EPSG:4326', 'EPSG:3857'),
zoom: 12
});
var myZoom = new ol.control.Zoom();
var myZoomSlider = new ol.control.ZoomSlider();
var zoomToExtentControl = new ol.control.ZoomToExtent({
extent: [1453297.22,7490484.81,1483872.03,7513415.91]
});
var myScaleLine = new ol.control.ScaleLine()
var neighborhood = new ol.source.ImageWMS({
url: 'http://localhost:8090/geoserver/project/wms',
params: {'LAYERS': 'project:Neighborhood'}
});
var roads = new ol.source.ImageWMS({
url: 'http://localhost:8090/geoserver/project/wms',
params: {'LAYERS': 'project:Roads_all'}
});
var source = new ol.source.Vector({wrapX: false});
vector = new ol.layer.Vector({
source: source,
style: new ol.style.Style({
fill: new ol.style.Fill({
color: 'rgba(0, 255, 0, 0.5)'
}),
stroke: new ol.style.Stroke({
color: '#ffcc33',
width: 2
}),
image: new ol.style.Circle({
radius: 7,
fill: new ol.style.Fill({
color: '#ffcc33'
})
})
})
});
var layers = [
new ol.layer.Image({
source: neighborhood
}),
new ol.layer.Image({
source: roads
}),
vector
]
map = new ol.Map({
layers: layers,
target: 'map',
view: view
});
map.addControl(myZoom);
map.addControl(myZoomSlider);
map.addControl(zoomToExtentControl);
map.addControl(myScaleLine);
map.on('singleclick', function(evt){
var coord = evt.coordinate;
transformed_coordinate = ol.proj.transform(coord, "EPSG:3857", "EPSG:4326");
//console.log(transformed_coordinate);
})
function onFeaturesAdded(event){
var bounds = event.features[0].geometry.getBounds();
var answer = "bottom: " + bounds.bottom + "\n";
answer += "left: " + bounds.left + "\n";
answer += "right: " + bounds.right + "\n";
answer += "top: " + bounds.top + "\n";
alert(answer);
}
var typeSelect = document.getElementById('type');
function addInteraction() {
var value = typeSelect.value;
if (value !== 'None') {
var geometryFunction, maxPoints;
if (value === 'Square') {
value = 'Circle';
geometryFunction = ol.interaction.Draw.createRegularPolygon(4);
} else if (value === 'Box') {
value = 'LineString';
maxPoints = 2;
geometryFunction = function(coordinates, geometry) {
if (!geometry) {
geometry = new ol.geom.Polygon(null);
}
var start = coordinates[0];
var end = coordinates[1];
geometry.setCoordinates([
[start, [start[0], end[1]], end, [end[0], start[1]], start]
]);
return geometry;
};
}
draw = new ol.interaction.Draw({
source: source,
type: /** @type {ol.geom.GeometryType} */ (value),
geometryFunction: geometryFunction,
maxPoints: maxPoints
});
map.addInteraction(draw);
}
}
/**
* Let user change the geometry type.
* @param {Event} e Change event.
*/
typeSelect.onchange = function(e) {
map.removeInteraction(draw);
addInteraction();
};
addInteraction();
} //end init
</script>
</head>
<body onload="init()">
<div id="map" style="width: 800px; height: 600px"></div>
<form class="form-inline">
<label>Geometry type </label>
<select id="type">
<option value="None">None</option>
<option value="Point">Point</option>
<option value="LineString">LineString</option>
<option value="Polygon">Polygon</option>
</select>
</form>
</body>
</html>
