Photos Not Being Geo-Tagged - How Can I Geo-tag Photos in my iPhone App?

Question

When you take photos with the iPhone camera, they are automatically geo-tagged.

I have written the following code to take photos in my GPS Recorder app, but the photos are not being geo-tagged.

What am I doing wrong? Should I be using a completely different method, or is there some way I can modify my code to add the geo-tag and other data to the EXIF info?

Note that self.photoInfo is the info dictionary returned by this delegate method:

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

Here's the code:

UIImage *oImage = [self.photoInfo objectForKey:UIImagePickerControllerOriginalImage];

CGSize size = oImage.size;

oImage = [CameraController imageWithImage:oImage 
  scaledToSize:CGSizeMake(size.width/2.56,size.height/2.56)];

NSDictionary *info = [[NSDictionary alloc] initWithObjectsAndKeys:
  oImage, @"image", titleString, @"title", nil];

TrailTrackerAppDelegate *t = (TrailTrackerAppDelegate *)[[UIApplication sharedApplication] delegate];
[NSThread detachNewThreadSelector:@selector(saveImage:) toTarget:t withObject:info];


+ (UIImage*)imageWithImage:(UIImage*)image scaledToSize:(CGSize)newSize {

  UIGraphicsBeginImageContext( newSize );
  [image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
  UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();

  return newImage;
}

Here is a photo taken with the Camera, which has all the good EXIF data: http://www.flickr.com/photos/33766454@N02/3978868900/

And here is on taken with my code, which doesn't have the EXIF data: http://www.flickr.com/photos/33766454@N02/3978860380/

Answer 1

UIImage does not really have any kind of EXIF, so you are not given an image with any EXIF. If you generate a JPG or PNG, you have to add any EXIF you need in place...