Openlayers3中实现台风风圈绘制算法

本文主要是介绍Openlayers3中实现台风风圈绘制算法，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

概述：

台风的风圈的NE、NW、SW、SE四个方位的影响范围是不一致，本文介绍一种简单的风圈的绘制方法，并在OL3中展示。

实现效果：

实现代码：

1、数据格式

			var Configs = {CIRCLE_CENTER_X:104.21390114106414,CIRCLE_CENTER_Y:35.847595169932646,CIRCLE_R:{"SE":0.5,"NE":0.3,"NW":0.2,"SW":0.5}};

2、关键代码

            var wkt = "POLYGON((";var wkt0 = "", _interval = 6;for(var i=0;i<360/_interval;i++){var _r = 0;var _ang = i*_interval;if(_ang>0&&_ang<=90){_r = Configs.CIRCLE_R.NE;}else if(_ang>90&&_ang<=180){_r = Configs.CIRCLE_R.NW;}else if(_ang>180&&_ang<=270){_r = Configs.CIRCLE_R.SW;}else{_r = Configs.CIRCLE_R.SE;}var x = Configs.CIRCLE_CENTER_X + _r * Math.cos(_ang * 3.14 /180);var y = Configs.CIRCLE_CENTER_Y + _r  * Math.sin(_ang * 3.14/180);wkt = wkt+""+x+" "+y+", ";if(i===0){wkt0 = ""+x+" "+y+"";}}wkt = wkt+wkt0+"))";

3、完整代码

<html xmlns="http://www.w3.org/1999/xhtml">
<head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title>Ol3 draw</title><link rel="stylesheet" type="text/css" href="../../../plugin/ol3/css/ol.css"/><style type="text/css">body, #map {border: 0px;margin: 0px;padding: 0px;width: 100%;height: 100%;font-size: 13px;}</style><script type="text/javascript" src="../../../plugin/ol3/build/ol.js"></script><script type="text/javascript" src="../../../plugin/jquery/jquery-1.8.3.js"></script><script type="text/javascript">var wktformat = new ol.format.WKT();function init(){var untiled = new ol.layer.Image({source: new ol.source.ImageWMS({ratio: 1,url: 'http://localhost:8080/geoserver/lzugis/wms',params: {'FORMAT': 'image/png','VERSION': '1.1.1',LAYERS: 'lzugis:province',STYLES: ''},serverType: 'geoserver'})});var Configs = {CIRCLE_CENTER_X:104.21390114106414,CIRCLE_CENTER_Y:35.847595169932646,CIRCLE_R:{"SE":0.5,"NE":0.3,"NW":0.2,"SW":0.5}};var wkt = "POLYGON((";var wkt0 = "", _interval = 6;for(var i=0;i<360/_interval;i++){var _r = 0;var _ang = i*_interval;if(_ang>0&&_ang<=90){_r = Configs.CIRCLE_R.NE;}else if(_ang>90&&_ang<=180){_r = Configs.CIRCLE_R.NW;}else if(_ang>180&&_ang<=270){_r = Configs.CIRCLE_R.SW;}else{_r = Configs.CIRCLE_R.SE;}var x = Configs.CIRCLE_CENTER_X + _r * Math.cos(_ang * 3.14 /180);var y = Configs.CIRCLE_CENTER_Y + _r  * Math.sin(_ang * 3.14/180);wkt = wkt+""+x+" "+y+", ";if(i===0){wkt0 = ""+x+" "+y+"";}}wkt = wkt+wkt0+"))";var features = new Array();features.push(wktformat.readFeature(wkt));features.push(wktformat.readFeature("POINT("+Configs.CIRCLE_CENTER_X+" "+Configs.CIRCLE_CENTER_Y+")"));var styleFunc = function(feature, resolution){var index = feature.get("index");return new ol.style.Style({fill: new ol.style.Fill({color: 'rgba(255, 0, 0, 0.2)'}),stroke: new ol.style.Stroke({color: '#ffcc33',width: 2}),image: new ol.style.Circle({radius: 4,fill: new ol.style.Fill({color: '#ff0000'})})});};var vector = new ol.layer.Vector({source: new ol.source.Vector({features: features}),style:styleFunc});var map = new ol.Map({controls: ol.control.defaults({attribution: false}),target: 'map',layers: [untiled,vector],view: new ol.View({projection: new ol.proj.Projection({code: 'EPSG:4326',units: 'degrees'}),center: [103.847, 36.0473],zoom: 4})});}</script>
</head>
<body onLoad="init()">
<div id="map">
</div>
</body>
</html>

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