Question

我正在尝试将行进的仪表转换为英里数。我遇到的问题是结果完全不准确，我找不到原因。

以下是我正在使用的代码：

CLLocation* newLocation = [locations lastObject];

NSTimeInterval age = -[newLocation.timestamp timeIntervalSinceNow];

if (age > 120) return;    //

if (newLocation.horizontalAccuracy < 0) return;


if (self.oldLocation == nil || self.oldLocation.horizontalAccuracy < 0) {
    self.oldLocation = newLocation;
    return;
}

CLLocationDistance distance = [newLocation distanceFromLocation: self.oldLocation];

NSLog(@"%6.6f/%6.6f to %6.6f/%6.6f for %2.0fm, accuracy +/-%2.0fm",
      self.oldLocation.coordinate.latitude,
      self.oldLocation.coordinate.longitude,
      newLocation.coordinate.latitude,
      newLocation.coordinate.longitude,
      distance,
      newLocation.horizontalAccuracy);

NSLog(@"distance is %f", distance);
totalDistanceBetween =+ (distance * 0.000621371192);
NSString *cycleDistanceString = [[NSString alloc]
                                 initWithFormat:@"%f meters",
                                 totalDistanceBetween];

_CurrentDistance.text = cycleDistanceString;
    self.oldLocation = newLocation;

任何人都可以告诉我哪里出错了吗？

由于

Answer 1

您的代码说明了这一点：

totalDistanceBetween =+ (distance * 0.000621371192);

使用一元+运算符，它不执行任何操作。你似乎意味着这个：

totalDistanceBetween += (distance * 0.000621371192);

此外，distance的单位是米（因为这是distanceFromLocation:返回的内容），totalDistanceBetween的单位是英里，因为0.000621371192英里= 1米。但在下一个语句中，您的格式字符串显示为%f meters。应该说%f miles。

将仪表转换为英里不准确的结果

1 个答案: