CLLocation distanceFromLocation large value

Question

我在CLLocation distanceFromLocation中遇到了一些問題。我有下面的代碼，格式化爲幫助調試，明確分配兩個新的位置等。無論哪種方式，兩個幾乎相同的位置導致巨大的差距，但只是有時。

代碼：

CLLocation *loc = [LightweightLocationTracker sharedLocationTracker].lastLocation; 
if (loc) 
{ 
    CLLocation *myLoc = [[CLLocation alloc] initWithLatitude:loc.coordinate.latitude longitude:loc.coordinate.longitude]; 
    CLLocation *productLoc = [[CLLocation alloc] initWithLatitude:self.productToView.latitude longitude:self.productToView.longitude];   
    CLLocationDistance dist = [myLoc distanceFromLocation:productLoc]; 

    NSLog(@"myLoc.coordinate.latitude %f", myLoc.coordinate.latitude);   
    NSLog(@"myLoc.coordinate.longitude %f", myLoc.coordinate.longitude);     
    NSLog(@"productLoc.coordinate.latitude %f", productLoc.coordinate.latitude); 
    NSLog(@"productLoc.coordinate.longitude %f", productLoc.coordinate.longitude); 
    NSLog(@"dist %f", dist);   
    NSLog(@"%1.1f km", dist); 
} 

一個運行TTY：

[] tapped main 
[] myLoc.coordinate.latitude 52.369200 
[] myLoc.coordinate.longitude 13.941100 
[] productLoc.coordinate.latitude 52.364400 
[] productLoc.coordinate.longitude 13.360600 
[] dist 39542.386770 
[] 39542.4 km 

另一個運行TTY：

[] myLoc.coordinate.latitude 52.369200 
[] myLoc.coordinate.longitude 13.941100 
[] productLoc.coordinate.latitude 52.369202 
[] productLoc.coordinate.longitude 13.941100 
[] dist 0.184915 
[] 0.2 km 

沒有看到的罪魁禍首......

Answer 1

好，distanceFromLocation回報會見ERS。所以30k的東西只有30km。聽起來對我來說完全合法。