我正在尝试使用Haversine距离公式但是我无法使用它,请参见以下代码
function test() { var lat2 = 42.741; var lon2 = -71.3161; var lat1 = 42.806911; var lon1 = -71.290611; var R = 6371; // km //has a problem with the .toRad() method below. var dLat = (lat2-lat1).toRad(); var dLon = (lon2-lon1).toRad(); var a = Math.sin(dLat/2) * Math.sin(dLat/2) + Math.cos(lat1.toRad()) * Math.cos(lat2.toRad()) * Math.sin(dLon/2) * Math.sin(dLon/2); var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)); var d = R * c; alert(d); }
错误是:
Uncaught TypeError: Object -0.06591099999999983 has no method 'toRad'
我知道这是因为它需要执行以下操作:
Number.prototype.toRad = function() { return this * Math.PI / 180; }
但是,当我将此放在函数下方时,它仍然返回相同的错误消息。如何使用助手方法?还是有其他方法可以对此进行编码?谢谢!
此代码有效:
Number.prototype.toRad = function() { return this * Math.PI / 180; } var lat2 = 42.741; var lon2 = -71.3161; var lat1 = 42.806911; var lon1 = -71.290611; var R = 6371; // km //has a problem with the .toRad() method below. var x1 = lat2-lat1; var dLat = x1.toRad(); var x2 = lon2-lon1; var dLon = x2.toRad(); var a = Math.sin(dLat/2) * Math.sin(dLat/2) + Math.cos(lat1.toRad()) * Math.cos(lat2.toRad()) * Math.sin(dLon/2) * Math.sin(dLon/2); var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)); var d = R * c; alert(d);