找出两个地方之间的路线数 [英] Find the number of routes between two places

问题描述

我需要找出使用Google maps API从来源到目的地的路线数量，然后找出哪一条路线是最短的路线。

I need to find out the number of routes from a source to a destination using the Google maps API, and then find, among those, which one is the shortest route.

我可以使用此代码获得一个路由

I am able to get one route by using this code

-(NSArray*) calculateRoutesFrom:(CLLocationCoordinate2D) f to: (CLLocationCoordinate2D) t {
    NSString* saddr = [NSString stringWithFormat:@"%f,%f", f.latitude, f.longitude];
    NSString* daddr = [NSString stringWithFormat:@"%f,%f", t.latitude, t.longitude];

    NSString* apiUrlStr = [NSString stringWithFormat:@"http://maps.google.com/maps?output=dragdir&saddr=%@&daddr=%@", saddr, daddr];
    NSURL* apiUrl = [NSURL URLWithString:apiUrlStr];
    NSLog(@"api url: %@", apiUrl);
    NSString *apiResponse = [NSString stringWithContentsOfURL:apiUrl];
    NSString* encodedPoints = [apiResponse stringByMatching:@"points:\\\"([^\\\"]*)\\\"" capture:1L];

    return [self decodePolyLine:[encodedPoints mutableCopy]];
}

<

but I'm unable to get multiple routes.

我是第一次使用Google Maps API;我按照本教程。

I'm new to using the Google Maps API; I followed this tutorial.

一个请张贴一些示例代码或教程？

How can I do this? Can any one please post some sample code or a tutorial?

推荐答案

true，指定Directions
服务可能在响应中提供多个
路由选择。
请注意，提供路由替换
可能会增加响应时间从
服务器。

alternatives (optional), if set to true, specifies that the Directions service may provide more than one route alternative in the response. Note that providing route alternatives may increase the response time from the server.

从 Google Directions API

您需要在查询中添加链接alternatives = true

You need to add in your query link alternatives=true

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