Question

Using http://maps.google.com/maps/geo?q=…. return latitude and longitude like those :
48.8616441,2.3448885

in a return string like this one :
200,8,48.8616441,2.3448885

When parsed a into a function that returns a CLLocationCoordinate2D :

    NSArray* listItems = [locationString componentsSeparatedByString:@","];

    CLLocationDegrees latitude = kInexistantLatitude;
    CLLocationDegrees longitude = kInexistantLongitude;

    if([listItems count] >= 4 && [[listItems objectAtIndex:0] isEqualToString:@"200"]) {
        latitude = [[listItems objectAtIndex:2] doubleValue];
        longitude = [[listItems objectAtIndex:3] doubleValue];
    }

    CLLocationCoordinate2D location;
    location.latitude = latitude;
    location.longitude = longitude;

    return location;

it gives into the debugger :

latitude = 48.861644099999999
longitude = 2.3448885000000002

I store many items like this one into an array, and at the end, I parse the array to write them into a plist file as dictionary items ( tag) (I use a NSString appendFormat that gives, like a NSLog) :

NSLog(@"%f %f", location.latitude, location.longitude);

48.861644 2.344889

At some moment, I will load that dictionary, and I will store that read stuff into a CLLocationCoordinate2D to display it on a MKMapView.

So I have 2 problems :

1) How may I store the returned value given by the http request without loosing a digit, and keeping my function ?

2) If I acheiev to do so, how may I read the stuff and store it into a CLLocationCoordinate2D without loosing again a digit ?

Answer 1

You are not losing a digit of precision. When you use

NSLog(@"%f %f", location.latitude, location.longitude);

If you do not specify a precision, %f automatically truncates your number to 6 decimal places as per the ANSI C standard.

Try

NSLog(@"%.8f %.8f", location.latitude, location.longitude);

This should return the same number as the return string.