<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>画图测量面积</title>
<link rel="stylesheet" href="css/ol.css">
<script src="js/jquery-1.11.3.js"></script>
<script src="js/ol.js"></script>
<style>
#map{
width:100%;
height:100%;
}
.tooltip {
position: relative;
background: rgba(0, 0, 0, 0.5);
border-radius: 4px;
color: white;
padding: 4px 8px;
opacity: 0.7;
white-space: nowrap;
}
.tooltip-measure {
opacity: 1;
font-weight: bold;
}
.tooltip-static {
background-color: #ffcc33;
color: black;
border: 1px solid white;
}
.tooltip-measure:before,
.tooltip-static:before {
border-top: 6px solid rgba(0, 0, 0, 0.5);
border-right: 6px solid transparent;
border-left: 6px solid transparent;
content: "";
position: absolute;
bottom: -6px;
margin-left: -7px;
left: 50%;
}
.tooltip-static:before {
border-top-color: #ffcc33;
}
</style>
</head>
<body>
<div id="map"></div>
<script>
var map=new ol.Map({
target:'map',
layers:[
new ol.layer.Tile({
source:new ol.source.OSM()
})
],
view:new ol.View({
center:[0,0],
zoom:2
})
});//初始化地图
var drawing_layer = new ol.layer.Vector({
source: new ol.source.Vector(),
style:new ol.style.Style({
fill:new ol.style.Fill({
color:"rgba(225,225,225,.2)"
}),
stroke:new ol.style.Stroke({
color:"#ffcc33",
width:2
}),
image:new ol.style.Circle({
radius:7,
fill:new ol.style.Fill({
color:"#ffcc33"
})
})
})
});// 画面积计算的图层
map.addLayer(drawing_layer);
var polygon_drawing_tool = new ol.interaction.Draw({
source: drawing_layer.getSource(),
type: 'Polygon',
style: new ol.style.Style({
fill: new ol.style.Fill({
color: '#ffcc33'
}),
stroke: new ol.style.Stroke({
color: '#ffcc33',
lineDash: [10, 10],
width: 3
}),
image: new ol.style.Circle({
radius: 5,
stroke: new ol.style.Stroke({
color: 'rgba(0, 0, 0, 0.7)'
}),
fill: new ol.style.Fill({
color: '#ffcc33'
})
})
})
});//绘图控件对象
var listener;//绑定交互绘制工具开始绘制事件
var measureTooltipElement;
polygon_drawing_tool.on('drawstart',function(evt) {
sketch = evt.feature;
var tooltipCoord = evt.coordinate;
listener = sketch.getGeometry().on('change', function(evt) {
var geom = evt.target;
var output = formatArea(/** @type {ol.geom.LineString} */ (geom));
tooltipCoord = geom.getLastCoordinate();
createMeasureTooltip();
measureTooltipElement.innerHTML = output;
measureTooltip.setPosition(tooltipCoord);
});
}, this);
polygon_drawing_tool.on('drawend',function() {
measureTooltipElement.className = 'tooltip tooltip-static';
measureTooltip.setOffset([0, -7]);
sketch = null;
measureTooltipElement = null;
createMeasureTooltip();
ol.Observable.unByKey(listener);
}, this);
var formatArea = function(polygon) {
var area=polygon.getArea();
var output;
if(area>10000){
output=(Math.round(area/1000000*100)/100)+' '+'km<sup>2</sup>';
}else{
output=(Math.round(area*100)/100)+' '+'m<sup>2</sup>';
}
return output;
};
function createMeasureTooltip() {
if (measureTooltipElement) {
measureTooltipElement.parentNode.removeChild(measureTooltipElement);
}
measureTooltipElement = document.createElement('div');
measureTooltipElement.className = 'tooltip tooltip-measure';
measureTooltip = new ol.Overlay({
element: measureTooltipElement,
offset: [0, -15],
positioning: 'bottom-center'
});
map.addOverlay(measureTooltip);
}
$(document).ready(function() {
map.addInteraction(polygon_drawing_tool);
});
</script>
</body>
</html>
