Draw Features——绘制要素
Example of using the Draw interaction. Select a geometry type from the dropdown above to start drawing. To finish drawing, click the last point. To activate freehand drawing for lines, polygons, and circles, hold
the
使用绘图交互控件的例子。从上面的下拉列表框中选择一种几何类型开始绘制。单击最后一个点完成绘制。按住shift键激活自由绘制线、多边形和圆形。
the
Shift key.使用绘图交互控件的例子。从上面的下拉列表框中选择一种几何类型开始绘制。单击最后一个点完成绘制。按住shift键激活自由绘制线、多边形和圆形。
代码：
<!DOCTYPE html>
<html>
<head>
<title>Draw Features</title>
<link rel="stylesheet" href="https://openlayers.org/en/v4.2.0/css/ol.css" type="text/css">
<!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
<script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script>
<script src="https://openlayers.org/en/v4.2.0/build/ol.js"></script>
</head>
<body>
<div id="map" class="map"></div>
<form class="form-inline">
<label>Geometry type </label>
<select id="type">
<option value="Point">Point</option>
<option value="LineString">LineString</option>
<option value="Polygon">Polygon</option>
<option value="Circle">Circle</option>
<option value="None">None</option>
</select>
</form>
<script>
var raster = new ol.layer.Tile({
source: new ol.source.OSM()
});
var source = new ol.source.Vector({wrapX: false});
var vector = new ol.layer.Vector({
source: source
});
var map = new ol.Map({
layers: [raster, vector],
target: 'map',
view: new ol.View({
center: [-11000000, 4600000],
zoom: 4
})
});
// 获取绘制几何体类型
var typeSelect = document.getElementById('type');
var draw; // global so we can remove it later // 全局变量因此我们可以稍后移除它
// 创建交互绘制对象并添加到map中
function addInteraction() {
var value = typeSelect.value;
if (value !== 'None') {
draw = new ol.interaction.Draw({
source: source,
type: /** @type {ol.geom.GeometryType} */ (typeSelect.value)
});
map.addInteraction(draw);
}
}
/**
* Handle change event. // 处理change事件
*/
typeSelect.onchange = function() {
map.removeInteraction(draw);
addInteraction();
};
addInteraction();
</script>
</body>
</html>转载自：https://blog.csdn.net/SmileCoffin/article/details/73897542
