前端获取围栏点的代码：
```
<!DOCTYPE html>
<html>
<head>
	<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
	<meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
	<script type="text/javascript" src="http://api.map.baidu.com/api?v=2.0&ak=***123132"></script>
	
    <script type="text/javascript" src="http://api.map.baidu.com/library/DrawingManager/1.4/src/DrawingManager_min.js"></script>
    <link rel="stylesheet" href="http://api.map.baidu.com/library/DrawingManager/1.4/src/DrawingManager_min.css" />

<title>鼠标绘制工具</title>
    <style>
body,html{width:100%;height:100%;margin:0;font-family:"微软雅黑"}
.btn-sm{padding:5px 10px;font-size:12px;line-height:1.5;border-radius:3px}
.btn-info{color:#fff;background-color:#3bb4f2;border-color:#3bb4f2}
.btn{display:inline-block;margin-bottom:0;font-weight:normal;text-align:center;vertical-align:middle;touch-action:manipulation;cursor:pointer;background-image:none;border:1px solid transparent;white-space:nowrap;padding:6px 12px;font-size:14px;line-height:1.42857143;border-radius:4px;-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none}
.btn-danger{color:#fff;background-color:#dd514c;border-color:#dd514c}
#result{position:fixed;bottom:0;right:0;padding:10px;background:#fff;border-radius:5px;border:1px solid #ccc;box-shadow:5px 5px 5px #bbb}
    </style>
</head>
<body>
    <div id="allmap" style="overflow:hidden;zoom:1;position:relative;">    
        <div id="map" style="height:100%;-webkit-transition: all 0.5s ease-in-out;transition: all 0.5s ease-in-out;"></div>
    </div>
    <div id="result">
        <input class="btn btn-sm btn-round btn-danger" type="button" value="保存" onclick="save()"/>
        <input class="btn btn-sm btn-round btn-danger" type="button" value="初始化" onclick="drawPolygon()"/>
        <input class="btn btn-sm btn-round btn-info" type="button" value="重置清除" onclick="clearAll()"/>
    </div>
</body>
</html>
<script src="http://libs.baidu.com/jquery/2.1.4/jquery.min.js"></script>
<script type="text/javascript">
$('#allmap').css('height', $(document).height()+'px')
    // 百度地图API功能
    var map = new BMap.Map('map');
    var poi = new BMap.Point(116.307852,40.057031);
    map.centerAndZoom(poi, 16);//设置中心点坐标和地图级别
    map.enableScrollWheelZoom(); //启用鼠标滚动对地图放大缩小
    // 创建地址解析器实例
    var myGeo = new BMap.Geocoder();
    // 将地址解析结果显示在地图上,并调整地图视野
    myGeo.getPoint("天河区", function(point){
        if (point) {
            map.centerAndZoom(point, 16);
            map.addOverlay(new BMap.Marker(point));
        }else{
            alert("您选择地址没有解析到结果!");
        }
    }, "天河区");

//鼠标绘制完成回调方法   获取各个点的经纬度
    var overlays = [];
    var json_data = [];
    var styleOptions = {
        strokeColor:"red",    //边线颜色。
        fillColor:"red",      //填充颜色。当参数为空时，圆形将没有填充效果。
        strokeWeight: 3,       //边线的宽度，以像素为单位。
        strokeOpacity: 0.8,       //边线透明度，取值范围0 - 1。
        fillOpacity: 0.6,      //填充的透明度，取值范围0 - 1。
        strokeStyle: 'solid' //边线的样式，solid或dashed。
    }
    //实例化鼠标绘制工具
    var drawingManager = new BMapLib.DrawingManager(map, {
        isOpen: false, //是否开启绘制模式
        enableDrawingTool: true, //是否显示工具栏
        drawingMode:BMAP_DRAWING_POLYGON,//绘制模式  多边形
        drawingToolOptions: {
            anchor: BMAP_ANCHOR_TOP_RIGHT, //位置
            offset: new BMap.Size(5, 5), //偏离值
            drawingModes:[
                BMAP_DRAWING_POLYGON
            ]
        },
        polygonOptions: styleOptions //多边形的样式
    });
    
     //添加鼠标绘制工具监听事件，用于获取绘制结果
    drawingManager.addEventListener('overlaycomplete', overlaycomplete);
    function overlaycomplete(e){
        overlays.push(e.overlay);
        var path = e.overlay.getPath();//Array<Point> 返回多边型的点数组
        for(var i=0;i<path.length;i++){
            console.log("lng:"+path[i].lng+"\n lat:"+path[i].lat);
            json_data.push({
                "lng":path[i].lng,
                "lat":path[i].lat
            });
        }
    };
    // 清除
    function clearAll() {
        // 清除初始化的覆盖物
        var allOverlay = map.getOverlays();
        for(var i = 0; i < allOverlay.length; i++) {
            map.removeOverlay(allOverlay[i]);
            map.removeOverlay(allOverlay[i+1]);
        }
        // 清除lbs的覆盖物
        for(var i = 0; i < overlays.length; i++){
            map.removeOverlay(overlays[i]);
        }
        
        json_data = [];
        overlays.length = 0   
    }
    $('.BMapLib_last').click(function() {
        clearAll();
    })
    // 初始化绘制
    function drawPolygon(){
        clearAll();
        let point = [
            {
                lng:113.358412,
                lat:23.139497
            },
            {
                lng:113.361358,
                lat:23.136008
            },
            {
                lng:113.358664,
                lat:23.129893
            },
            {
                lng:113.370593,
                lat:23.139198
            },
            {
                lng:113.370377,
                lat:23.139165
            }
        ];
       
        let polArry = [];
        point.forEach(item => {
            let p = new BMap.Point(item.lng,item.lat);
            polArry.push(p);
            // 初始化参数，防止初始化之后，又立刻提交
            json_data.push({
                "lng":item.lng,
                "lat":item.lat
            });
        });
        let polygon = new BMap.Polygon(polArry,styleOptions);
        map.addOverlay(polygon);
    }
    // 保存
    function save() {
        console.log(json_data);
        
    }
</script>
```

PHP过滤围栏的SDK：
```php
<?php
// +----------------------------------------------------------------------
// | PHP地理围栏过滤判断
// +----------------------------------------------------------------------
// | Copyright (c) 2018 https://blog.junphp.com All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: 小黄牛 <1731223728@qq.com>
// +----------------------------------------------------------------------
 
class LbsBaiDu{
    /**
     * 圆周率
    */
    private $PI = 3.14159265358979324;
 
    /**
     * 判断一个坐标是否在圆内
     * 思路：判断此点的经纬度到圆心的距离  然后和半径做比较
     * 如果此点刚好在圆上 则返回true
     * @param $point ['lng'=>'','lat'=>''] array指定点的坐标
     * @param $circle array ['center'=>['lng'=>'','lat'=>''],'radius'=>'']  中心点和半径
     */
    public function is_circle($point, $circle){
        $distance = $this -> distance($point['lat'],$point['lng'],$circle['center']['lat'],$circle['center']['lng']);
        if($distance <= $circle['radius']){
            return true;
        }else{
            return false;
        }
    }
 
    /**
     * 判断一个坐标是否在一个多边形内（由多个坐标围成的）
     * 基本思想是利用射线法，计算射线与多边形各边的交点，如果是偶数，则点在多边形外，否则
     * 在多边形内。还会考虑一些特殊情况，如点在多边形顶点上，点在多边形边上等特殊情况。
     * @param $point 指定点坐标
     * @param $pts 多边形坐标 顺时针方向
     */
    public function is_polygon($point, $pts) {
        $N = count($pts);
        $boundOrVertex = true; //如果点位于多边形的顶点或边上，也算做点在多边形内，直接返回true
        $intersectCount = 0;//cross points count of x
        $precision = 2e-10; //浮点类型计算时候与0比较时候的容差
        $p1 = 0;//neighbour bound vertices
        $p2 = 0;
        $p = $point; //测试点
 
        $p1 = $pts[0];//left vertex
        for ($i = 1; $i <= $N; ++$i) {//check all rays
            // dump($p1);
            if ($p['lng'] == $p1['lng'] && $p['lat'] == $p1['lat']) {
                return $boundOrVertex;//p is an vertex
            }
 
            $p2 = $pts[$i % $N];//right vertex
            if ($p['lat'] < min($p1['lat'], $p2['lat']) || $p['lat'] > max($p1['lat'], $p2['lat'])) {//ray is outside of our interests
                $p1 = $p2;
                continue;//next ray left point
            }
 
            if ($p['lat'] > min($p1['lat'], $p2['lat']) && $p['lat'] < max($p1['lat'], $p2['lat'])) {//ray is crossing over by the algorithm (common part of)
                if($p['lng'] <= max($p1['lng'], $p2['lng'])){//x is before of ray
                    if ($p1['lat'] == $p2['lat'] && $p['lng'] >= min($p1['lng'], $p2['lng'])) {//overlies on a horizontal ray
                        return $boundOrVertex;
                    }
 
                    if ($p1['lng'] == $p2['lng']) {//ray is vertical
                        if ($p1['lng'] == $p['lng']) {//overlies on a vertical ray
                            return $boundOrVertex;
                        } else {//before ray
                            ++$intersectCount;
                        }
                    } else {//cross point on the left side
                        $xinters = ($p['lat'] - $p1['lat']) * ($p2['lng'] - $p1['lng']) / ($p2['lat'] - $p1['lat']) + $p1['lng'];//cross point of lng
                        if (abs($p['lng'] - $xinters) < $precision) {//overlies on a ray
                            return $boundOrVertex;
                        }
 
                        if ($p['lng'] < $xinters) {//before ray
                            ++$intersectCount;
                        }
                    }
                }
            } else {//special case when ray is crossing through the vertex
                if ($p['lat'] == $p2['lat'] && $p['lng'] <= $p2['lng']) {//p crossing over p2
                    $p3 = $pts[($i+1) % $N]; //next vertex
                    if ($p['lat'] >= min($p1['lat'], $p3['lat']) && $p['lat'] <= max($p1['lat'], $p3['lat'])) { //p.lat lies between p1.lat & p3.lat
                        ++$intersectCount;
                    } else {
                        $intersectCount += 2;
                    }
                }
            }
            $p1 = $p2;//next ray left point
        }
 
        if ($intersectCount % 2 == 0) {//偶数在多边形外
            return false;
        } else { //奇数在多边形内
            return true;
        }
    }
    
    /**
     *  计算两个点之间的距离
     * @param $latA  第一个点的纬度
     * @param $lonA  第一个点的经度
     * @param $latB  第二个点的纬度
     * @param $lonB  第二个点的经度
     * @return float
     */
    private function distance($latA, $lonA, $latB, $lonB) {
        $earthR = 6371000.;
        $x = cos($latA * $this->PI / 180.) * cos($latB * $this->PI / 180.) * cos(($lonA - $lonB) * $this->PI / 180);
        $y = sin($latA * $this->PI / 180.) * sin($latB * $this->PI / 180.);
        $s = $x + $y;
        if ($s > 1) $s = 1;
        if ($s < -1) $s = -1;
        $alpha = acos($s);
        $distance = $alpha * $earthR;
        return $distance;
    }
}
```

SDK的用法：
```php
include_once './LbsBaiDu.php';
$convert = new LbsBaiDu();

// 判断圆内
$point = ['lng'=>116.394299,'lat'=>40.011674];
$circle = [
    'center'=>['lng'=>116.12637,'lat'=>40.114308],
    'radius'=>46807.83038795571
];
$bool = $convert->is_circle($point,$circle);
var_dump($bool);

// 判断多边形内
$pts = [
    ['lng'=>115.934109, 'lat'=>40.124809],
    ['lng'=>116.554836, 'lat'=>40.177293],
    ['lng'=>116.620754, 'lat'=>39.783734],
    ['lng'=>116.054958, 'lat'=>39.809057]
];
$point = ['lng'=>115.989864,'lat'=>39.973272];
$bool = $convert->is_polygon($point,$pts);
var_dump($bool);
```

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