是否有数学计算来通过谷歌的 Elevation API 定义点 A 和点 B 之间是否可见？
有没有办法通过google API获取海拔剖面数据来检查两点之间是否有视线？
例如，我可以通过此链接获取海拔剖面图：https ://maps.googleapis.com/maps/api/elevation/json?path=36.578581,-118.291994|36.23998,-116.83171&samples=10&key=YOUR_API_KEY
结果是一个 json，其中 10 个点位于两点之间，地面高程，例如：
{
"results" : [
{
"elevation" : 4411.94189453125,
"location" : {
"lat" : 36.578581,
"lng" : -118.291994
},
"resolution" : 19.08790397644043
},
{
"elevation" : 1658.561645507812,
"location" : {
"lat" : 36.54183904164596,
"lng" : -118.1291141726249
},
"resolution" : 9.543951988220215
},
{
"elevation" : 1085.295776367188,
"location" : {
"lat" : 36.50487579522382,
"lng" : -117.966389550823
},
"resolution" : 9.543951988220215
},
{
"elevation" : 1491.4912109375,
"location" : {
"lat" : 36.46769177008888,
"lng" : -117.8038207060907
},
"resolution" : 9.543951988220215
},
{
"elevation" : 1583.762817382812,
"location" : {
"lat" : 36.43028747728768,
"lng" : -117.6414082023003
},
"resolution" : 9.543951988220215
},
{
"elevation" : 488.8834228515625,
"location" : {
"lat" : 36.39266342953181,
"lng" : -117.4791525957044
},
"resolution" : 9.543951988220215
},
{
"elevation" : 933.0382080078125,
"location" : {
"lat" : 36.35482014117158,
"lng" : -117.3170544349424
},
"resolution" : 9.543951988220215
},
{
"elevation" : 1657.123779296875,
"location" : {
"lat" : 36.31675812816988,
"lng" : -117.1551142610472
},
"resolution" : 9.543951988220215
},
}
],
"status" : "OK"
}
是否有数学公式来检查是否可以看到 A 点和 B 点？
我需要用 PHP 编写代码。
鸿蒙传说1回答
-
慕勒3428872
鉴于您正在沿着一条直线处理 2 个点，我认为处理此问题的最简单方法是从 2D 角度查看它，其中 x 轴表示您的样本编号，y 轴表示你的高度。然后我们假设如果结果 n 处的高程高于直线，则视线中断。在哪里：(x1, y1) = (1, 4411.94)(x2, y2) = (10, -84.51)这是绘制出的结果的图片以及在其上绘制的从一点到另一点的线：我们可以看到样本 8 和 9 的视线被打破了。下面是查找相同内容的代码。它使用直线的基本方程：y = mx + c$results_json = json_decode('{"results":[{"elevation":4411.94189453125,"location":{"lat":36.578581,"lng":-118.291994},"resolution":19.08790397644043},{"elevation":1658.561645507812,"location":{"lat":36.54183904164596,"lng":-118.1291141726249},"resolution":9.543951988220215},{"elevation":1085.295776367188,"location":{"lat":36.50487579522382,"lng":-117.966389550823},"resolution":9.543951988220215},{"elevation":1491.4912109375,"location":{"lat":36.46769177008888,"lng":-117.8038207060907},"resolution":9.543951988220215},{"elevation":1583.762817382812,"location":{"lat":36.43028747728768,"lng":-117.6414082023003},"resolution":9.543951988220215},{"elevation":488.8834228515625,"location":{"lat":36.39266342953181,"lng":-117.4791525957044},"resolution":9.543951988220215},{"elevation":933.0382080078125,"location":{"lat":36.35482014117158,"lng":-117.3170544349424},"resolution":9.543951988220215},{"elevation":1657.123779296875,"location":{"lat":36.31675812816988,"lng":-117.1551142610472},"resolution":9.543951988220215},{"elevation":1074.835205078125,"location":{"lat":36.27847790807609,"lng``":-116.9933326074523},"resolution":9.543951988220215},{"elevation":-84.51690673828125,"location":{"lat":36.23998,"lng":-116.83171},"resolution":9.543951988220215}],"status":"OK"}');$x1 = 0;$x2 = count($results_json->results);$y1 = $results_json->results[0]->elevation;$y2 = $results_json->results[$x2 - 1]->elevation; // last result in results array$m = ($y2 - $y1) / ($x2 - $x1); // slope of the line$c = $y2 - ($m * $x2);$i = 0;foreach ($results_json->results as $result){ $elevation_of_straight_line = ($m * $i) + $c; $elevation_of_result = $result->elevation; if ($elevation_of_result > $elevation_of_straight_line){ echo 'line of sight broken'; echo 'Elevation of sample index '.$i.' = '.$elevation_of_result; echo 'Elevation of line of sight = '.$elevation_of_straight_line; } $i++;}这消除了从 3D 角度看这个问题所带来的复杂性。尽管在地球曲率发挥作用的情况下，这有其缺点。这也应该可以根据需要扩展到尽可能多的样本。
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PHP