Openlayers3中实现台风风圈绘制算法

云游屋•2022-09-01•地图开发• 997

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。

效果

台风风圈

代码

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
                }
            };

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+"))";

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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