dart实现经纬度两点坐标之间距离计算

代码如下：

import 'dart:math';

void main() {
  print("distance between two point is : ${getDistance(
      119.9831030000, 30.2340350000, 119.9809580000, 30.2320980000)}");
}

getDistance(double lat1, double lng1, double lat2, double lng2) {
  double radLat1 = rad(lat1);
  double radLat2 = rad(lat2);
  double a = radLat1 - radLat2;
  double b = rad(lng1) - rad(lng2);
  double s = 2 *
      asin(sqrt(pow(sin(a / 2), 2) +
          cos(radLat1) * cos(radLat2) * pow(sin(b / 2), 2)));
  return s * 6378138.0;
}

double rad(double d) {
  return d * pi / 180.0;
}

选取两点作为例子：

1. 赞成乐山红叶北门（Latitude: 119.9831030000, Longitude: 30.2340350000）
2. 闲林街道办事处（Latitude: 119.9809580000, Longitude: 30.2320980000）
   运行结果：

distance between two point is : 261.9676660067193

从一个测经纬度距离的网站测试的结果如下:

image.png