Question

在应用程序中，我需要计算两点之间的距离。我是这样做的。

- (void)locationManager:(CLLocationManager *)manager
    didUpdateToLocation:(CLLocation *)newLocation
           fromLocation:(CLLocation *)oldLocation{
    NSLog(@"updating");
     //Getting my concerts
    arrConcerten = [matches mutableCopy];

       for (Event *concert in arrConcerten) {
            CLLocation *restaurnatLoc = [[CLLocation alloc] initWithLatitude:[concert.eve_latitude floatValue] longitude:[concert.eve_longitude floatValue]];

            CLLocationDistance meters = [restaurnatLoc distanceFromLocation:newLocation];
            NSLog(@"meters are %f",meters);
            if(meters > 5000){
                [locationManager2 stopUpdatingLocation];
                NSString *message2 = [NSString stringWithFormat:@"Long = %f and lat= %f and Concert Lat = %f and long = %f",newLocation.coordinate.longitude,newLocation.coordinate.latitude,[concert.eve_latitude floatValue],[concert.eve_longitude floatValue]];
                NSLog(@"%@",message2);
            }else{

                NSLog(@"too far away");
            }

        }
    }

这就是我的日志所说的。

2013-10-17 15:57:23.518 Domino[7468:907] meters are 7973.753294
2013-10-17 15:57:23.520 Domino[7468:907] Long = 5.621456 and lat= 51.097340 and Concert Lat = 51.038139 and long = 5.557330
2013-10-17 15:57:23.896 Domino[7468:907] meters are 27850.874245
2013-10-17 15:57:23.899 Domino[7468:907] Long = 5.621456 and lat= 51.097340 and Concert Lat = 50.860332 and long = 5.493722

您可以看到，这些位置彼此靠近。但它仍然说我们太遥远了。有人可以帮帮我吗？

Answer 1

你为什么要用这个：

如果它超过5000米：做一些事情，否则太远了？我不明白逻辑。如果距离太远则超过5000米。所以我想：

  - (void)locationManager:(CLLocationManager *)manager
        didUpdateToLocation:(CLLocation *)newLocation
               fromLocation:(CLLocation *)oldLocation{
        NSLog(@"updating");
         //Getting my concerts
        arrConcerten = [matches mutableCopy];

       for (Event *concert in arrConcerten) {
            CLLocation *restaurnatLoc = [[CLLocation alloc] initWithLatitude:[concert.eve_latitude floatValue] longitude:[concert.eve_longitude floatValue]];

            CLLocationDistance meters = [restaurnatLoc distanceFromLocation:newLocation];
            NSLog(@"meters are %f",meters);
            if(meters <= 5000){
                [locationManager2 stopUpdatingLocation];
                NSString *message2 = [NSString stringWithFormat:@"Long = %f and lat= %f and Concert Lat = %f and long = %f",newLocation.coordinate.longitude,newLocation.coordinate.latitude,[concert.eve_latitude floatValue],[concert.eve_longitude floatValue]];
                NSLog(@"%@",message2);
            }else{

                NSLog(@"too far away");
            }

        }
    }

或者是corse：

if(meters > 5000){

                    NSLog(@"it's far enough");
 }else{

                    NSLog(@"too close");
 }

还有一件非常重要的事情：

此方法通过跟踪测量两个位置之间的距离它们之间的一条线跟随地球的曲率。该产生的弧线是一条平滑的曲线并没有考虑在内两个位置之间的特定高度变化。来自apple documentation

distanceFromLocation测量“在空中”的距离，而不是逐个测量的距离。

Answer 2

这是解决方案 -

-(NSString *)getDistance:(NSDictionary *)dicVal{
    CLLocation *pinLocation = [[CLLocation alloc] initWithLatitude:[[dicVal valueForKey:@"latitude"] doubleValue] longitude:[[dicVal valueForKey:@"longitude"] doubleValue]];

    CLLocation *userLocation = [[CLLocation alloc] initWithLatitude:appDelegate.userLocation.latitude longitude:appDelegate.userLocation.longitude];

    CLLocationDistance distance = [pinLocation distanceFromLocation:userLocation];
    NSString *dist=[NSString stringWithFormat:@"%4.0f %@", distance/1000,NSLocalizedString(@"KM", nil)];
    return dist;
}

Answer 3

是的，它只是每次cllocation经理必须分配的分配问题，如下所示：

LocationManager = [[[CLLocationManager alloc] init] autorelease];
LocationManager.delegate = self;
LocationManager.desiredAccuracy = kCLLocationAccuracyBest;
LocationManager.distanceFilter = kCLDistanceFilterNone;
[LocationManager startUpdatingLocation];
CLLocation *location = [LocationManager location];
CLLocationCoordinate2D coordinate1 = [location coordinate];


CLLocation *currentLoc = [[CLLocation alloc] initWithLatitude:coordinate1.latitude longitude:coordinate1.longitude];
CLLocation *restaurnatLoc = [[CLLocation alloc] initWithLatitude:l@"Your latitude not current" longitude:@"Your longitude not current'];
CLLocationDistance meters = [restaurnatLoc distanceFromLocation:currentLoc];    


if (meters > 1000)
{
    Distancelbl.text=[NSString stringWithFormat: @"You are Away %.2f Km",meters];
}
else{
    Distancelbl.text=[NSString stringWithFormat: @"You are Away %.2f Mtr",meters];
}

`

distanceFromLocation似乎不起作用

3 个答案: