要在谷歌地图上计算距离，您可以使用方向API。这是最简单的方法之一。要从谷歌服务器获取数据，您可以使用Retrofit或Volley。两者都有各自的优势。看看下面的代码，我使用了改造来实现它:

private void build_retrofit_and_get_response(String type) {

    String url = "https://maps.googleapis.com/maps/";

    Retrofit retrofit = new Retrofit.Builder()
            .baseUrl(url)
            .addConverterFactory(GsonConverterFactory.create())
            .build();

    RetrofitMaps service = retrofit.create(RetrofitMaps.class);

    Call<Example> call = service.getDistanceDuration("metric", origin.latitude + "," + origin.longitude,dest.latitude + "," + dest.longitude, type);

    call.enqueue(new Callback<Example>() {
        @Override
        public void onResponse(Response<Example> response, Retrofit retrofit) {

            try {
                //Remove previous line from map
                if (line != null) {
                    line.remove();
                }
                // This loop will go through all the results and add marker on each location.
                for (int i = 0; i < response.body().getRoutes().size(); i++) {
                    String distance = response.body().getRoutes().get(i).getLegs().get(i).getDistance().getText();
                    String time = response.body().getRoutes().get(i).getLegs().get(i).getDuration().getText();
                    ShowDistanceDuration.setText("Distance:" + distance + ", Duration:" + time);
                    String encodedString = response.body().getRoutes().get(0).getOverviewPolyline().getPoints();
                    List<LatLng> list = decodePoly(encodedString);
                    line = mMap.addPolyline(new PolylineOptions()
                                    .addAll(list)
                                    .width(20)
                                    .color(Color.RED)
                                    .geodesic(true)
                    );
                }
            } catch (Exception e) {
                Log.d("onResponse", "There is an error");
                e.printStackTrace();
            }
        }

        @Override
        public void onFailure(Throwable t) {
            Log.d("onFailure", t.toString());
        }
    });

}

上面是用于计算距离的函数build_retrofit_and_get_response的代码。下面是对应的改装界面:

package com.androidtutorialpoint.googlemapsdistancecalculator;


import com.androidtutorialpoint.googlemapsdistancecalculator.POJO.Example;

import retrofit.Call;
import retrofit.http.GET;
import retrofit.http.Query;

public interface RetrofitMaps {


/*
 * Retrofit get annotation with our URL
 * And our method that will return us details of student.
 */
@GET("api/directions/json?key=AIzaSyC22GfkHu9FdgT9SwdCWMwKX1a4aohGifM")
Call<Example> getDistanceDuration(@Query("units") String units, @Query("origin") String origin, @Query("destination") String destination, @Query("mode") String mode);

}

我希望这能解释你的问题。祝一切顺利:)

来源:谷歌地图距离计算器

离线解-哈弗辛算法

在Javascript中

var _eQuatorialEarthRadius = 6378.1370;
var _d2r = (Math.PI / 180.0);

function HaversineInM(lat1, long1, lat2, long2)
{
    return (1000.0 * HaversineInKM(lat1, long1, lat2, long2));
}

function HaversineInKM(lat1, long1, lat2, long2)
{
    var dlong = (long2 - long1) * _d2r;
    var dlat = (lat2 - lat1) * _d2r;
    var a = Math.pow(Math.sin(dlat / 2.0), 2.0) + Math.cos(lat1 * _d2r) * Math.cos(lat2 * _d2r) * Math.pow(Math.sin(dlong / 2.0), 2.0);
    var c = 2.0 * Math.atan2(Math.sqrt(a), Math.sqrt(1.0 - a));
    var d = _eQuatorialEarthRadius * c;

    return d;
}

var meLat = -33.922982;
var meLong = 151.083853;


var result1 = HaversineInKM(meLat, meLong, -32.236457779983745, 148.69094705162837);
var result2 = HaversineInKM(meLat, meLong, -33.609020205923713, 150.77061469270831);

C#

using System;

public class Program
{
    public static void Main()
    {
        Console.WriteLine("Hello World");

        var meLat = -33.922982;
        double meLong = 151.083853;


        var result1 = HaversineInM(meLat, meLong, -32.236457779983745, 148.69094705162837);
        var result2 = HaversineInM(meLat, meLong, -33.609020205923713, 150.77061469270831);

        Console.WriteLine(result1);
        Console.WriteLine(result2);
    }

    static double _eQuatorialEarthRadius = 6378.1370D;
    static double _d2r = (Math.PI / 180D);

    private static int HaversineInM(double lat1, double long1, double lat2, double long2)
    {
        return (int)(1000D * HaversineInKM(lat1, long1, lat2, long2));
    }

    private static  double HaversineInKM(double lat1, double long1, double lat2, double long2)
    {
        double dlong = (long2 - long1) * _d2r;
        double dlat = (lat2 - lat1) * _d2r;
        double a = Math.Pow(Math.Sin(dlat / 2D), 2D) + Math.Cos(lat1 * _d2r) * Math.Cos(lat2 * _d2r) * Math.Pow(Math.Sin(dlong / 2D), 2D);
        double c = 2D * Math.Atan2(Math.Sqrt(a), Math.Sqrt(1D - a));
        double d = _eQuatorialEarthRadius * c;

        return d;
    }
}

参考: https://en.wikipedia.org/wiki/Great-circle_distance

对于谷歌，你可以使用球面api, google.maps.geometry. sphere.computedistancebetween (latLngA, latLngB);

然而，如果球面投影或哈弗辛解的精度对你来说不够精确(例如，如果你靠近极点或计算更长的距离)，你应该使用不同的库。

关于这个主题的大部分信息我都是在维基百科上找到的。

要查看任何给定算法的精度是否足够，一个技巧是填充地球的最大和最小半径，并查看差异是否会给您的用例带来问题。更多细节可以在本文中找到

最后，谷歌api或haversine将毫无问题地满足大多数目的。

在我的情况下，这是最好的计算在SQL Server，因为我想采取当前位置，然后搜索所有邮政编码从当前位置一定距离内。我还有一个数据库，其中包含邮政编码及其纬度的列表。干杯

--will return the radius for a given number
create function getRad(@variable float)--function to return rad
returns float
as
begin
declare @retval float 
select @retval=(@variable * PI()/180)
--print @retval
return @retval
end
go

--calc distance
--drop function dbo.getDistance
create function getDistance(@cLat float,@cLong float, @tLat float, @tLong float)
returns float
as
begin
declare @emr float
declare @dLat float
declare @dLong float
declare @a float
declare @distance float
declare @c float

set @emr = 6371--earth mean 
set @dLat = dbo.getRad(@tLat - @cLat);
set @dLong = dbo.getRad(@tLong - @cLong);
set @a = sin(@dLat/2)*sin(@dLat/2)+cos(dbo.getRad(@cLat))*cos(dbo.getRad(@tLat))*sin(@dLong/2)*sin(@dLong/2);
set @c = 2*atn2(sqrt(@a),sqrt(1-@a))
set @distance = @emr*@c;
set @distance = @distance * 0.621371 -- i needed it in miles
--print @distance
return @distance;
end 
go


--get all zipcodes within 2 miles, the hardcoded #'s would be passed in by C#
select *
from cityzips a where dbo.getDistance(29.76,-95.38,a.lat,a.long) <3
order by zipcode

示例使用GPS的纬度/经度2个点。

var latitude1 = 39.46;
var longitude1 = -0.36;
var latitude2 = 40.40;
var longitude2 = -3.68;

var distance = google.maps.geometry.spherical.computeDistanceBetween(new google.maps.LatLng(latitude1, longitude1), new google.maps.LatLng(latitude2, longitude2));       

//p1 and p2 are google.maps.LatLng(x,y) objects

function calcDistance(p1, p2) {
          var d = (google.maps.geometry.spherical.computeDistanceBetween(p1, p2) / 1000).toFixed(2);
          console.log(d);              
}