is point in polygon

test.php

<?php

function is_point_in_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;
    }
}

/**
 * @name 围栏算法，判断一个坐标，是否在围栏里面.如：['113.664673,34.810146','113.681667,34.796896','113.69231,34.794711','113.702009,34.809159']
 * @param array $fences 围栏，是一组坐标数组 如：113.674458,34.804719
 * @param string $point
 * @return bool
 */
function in_fences($fences, $point) {
    $nvert = count($fences);
    $vertx = [];
    $verty = [];
    list($testy, $testx) = explode(',', $point);
    foreach ($fences as $r) {
        list($lng, $lat) = explode(',', $r);
        $vertx[] = $lat;
        $verty[] = $lng;
    }
    $i = $j = $c = 0;
    for ($i = 0, $j = $nvert - 1; $i < $nvert; $j = $i++) {
        if (( ($verty[$i] > $testy) != ($verty[$j] > $testy) ) &&
            ($testx < ($vertx[$j] - $vertx[$i]) * ($testy - $verty[$i]) / ($verty[$j] - $verty[$i]) + $vertx[$i]))
            $c = !$c;
    }
    return $c;
}

/**
 * 判断某个经纬度是否在多边形范围内
 * @param type $polygon
 * @param type $lnglat
 * @return boolean
 */
function isPointInPolygon($polygon, $lnglat) {
    $count = count($polygon);
    $px = $lnglat['lat'];
    $py = $lnglat['lng'];
    $flag = FALSE;
    for ($i = 0, $j = $count - 1; $i < $count; $j = $i, $i++) {
        $sy = $polygon[$i]['lng'];
        $sx = $polygon[$i]['lat'];
        $ty = $polygon[$j]['lng'];
        $tx = $polygon[$j]['lat'];
        if ($px == $sx && $py == $sy || $px == $tx && $py == $ty) {
            return TRUE;
        }
        if ($sy < $py && $ty >= $py || $sy >= $py && $ty < $py) {
            $x = $sx + ($py - $sy) * ($tx - $sx) / ($ty - $sy);
            if ($x == $px) {
                return TRUE;
            }
            if ($x > $px) {
                $flag = !$flag;
            }
        }
    }
    return $flag;
}