Problem in writing metadata to image

Question

I am using AvFoundation to take still image and adding gps info to metadata and saving to a photo album using Asset library but gps info is not saving at all.

here

Answer 1

Mason's answer really helped me. You'll need some modifications such as setting the absolute value of longitude & latitude. Here's a code snippet of using CoreLocation + Image I/O to write an UIImage to disk with GPS information:

- (BOOL)writeCGImage:(CGImageRef)theImage toURL:(NSURL*)url withType:(CFStringRef)imageType andOptions:(CFDictionaryRef)options {
    CGImageDestinationRef myImageDest   = CGImageDestinationCreateWithURL((CFURLRef)url, imageType, 1, nil);
    CGImageDestinationAddImage(myImageDest, theImage, options);
    BOOL success                        = CGImageDestinationFinalize(myImageDest);

    // Memory Mangement
    CFRelease(myImageDest);
    if (options)
        CFRelease(options);

    return success;
}

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {
    if (newLocation) {
        [manager stopUpdatingLocation];

        // Create formatted date
        NSTimeZone      *timeZone   = [NSTimeZone timeZoneWithName:@"UTC"];
        NSDateFormatter *formatter  = [[NSDateFormatter alloc] init]; 
        [formatter setTimeZone:timeZone];
        [formatter setDateFormat:@"HH:mm:ss.SS"];

        // Create GPS Dictionary
        NSDictionary *gpsDict   = [NSDictionary dictionaryWithObjectsAndKeys:
                                     [NSNumber numberWithFloat:fabs(newLocation.coordinate.latitude)], kCGImagePropertyGPSLatitude
                                   , ((newLocation.coordinate.latitude >= 0) ? @"N" : @"S"), kCGImagePropertyGPSLatitudeRef
                                   , [NSNumber numberWithFloat:fabs(newLocation.coordinate.longitude)], kCGImagePropertyGPSLongitude
                                   , ((newLocation.coordinate.longitude >= 0) ? @"E" : @"W"), kCGImagePropertyGPSLongitudeRef
                                   , [formatter stringFromDate:[newLocation timestamp]], kCGImagePropertyGPSTimeStamp
                                   , nil];

        // Memory Management
        [formatter release];

        // Set GPS Dictionary to be part of media Metadata
        // NOTE: mediaInfo in this sample is dictionary object returned in UIImagePickerController delegate:
        // imagePickerController:didFinishPickingMediaWithInfo
        if (mediaInfo && [mediaInfo objectForKey:UIImagePickerControllerMediaMetadata] && gpsDict) {
            [[mediaInfo objectForKey:UIImagePickerControllerMediaMetadata] setValue:gpsDict forKey:@"{GPS}"];
        }

        // Save Image
        if([self writeCGImage:[image CGImage] toURL:imageSaveURL withType:kUTTypeJPEG andOptions:(CFDictionaryRef)[mediaInfo objectForKey:UIImagePickerControllerMediaMetadata]]) {
            // Image is written to device
        }
    } 
}