Extract GPS data from photo

Question

I have a hard time because I want to extract the GPS coordinates from a photo. I use the function imagePickerController:didFinishPickingMediaWithInfo to pick an image and the I am inserting that image in a collectionView using the new Photos framework. I want to extract the GPS coordinates from the photo. I have done some research and I am aware of the fact that UIImage does not contain all the metadata, so I tried using the AssetsLibrary framework. Inside didFinishPickingMediaWithInfo I am using the following code to extract the photo location:

    var referenceURL : NSURL = info.objectForKey(UIImagePickerControllerReferenceURL) as NSURL
    var library : ALAssetsLibrary = ALAssetsLibrary()
    library.assetForURL(referenceURL, resultBlock: { (asset : ALAsset!) -> Void in
        var rep : ALAssetRepresentation = asset.defaultRepresentation()
        var metadata : NSDictionary = rep.metadata()


        let location: AnyObject! = asset.valueForProperty(ALAssetPropertyLocation)
        if location != nil {
            println(location)
        }
        else
        {
            println("Location not found")
        }


         })
    {
            (error : NSError!) -> Void in
    }

However, it doesn't find the location, even though I checked the image and it contains EXIF metadata (it contains also GPS locations, in which I am interested in). How can I retrieve the coordinates from photo?

Answer 1

With iOS 11 everything becomes much easier to recover GPS coordinate from a picture in your photo roll.

First import the Photo SDK

import Photos

Then before pushing the UIImagePickerController, ask the authorisation to access the data :

if PHPhotoLibrary.authorizationStatus() == .notDetermined {
    PHPhotoLibrary.requestAuthorization { [weak self](_) in
        // Present the UIImagePickerController
        self?.present(picker, animated: true, completion: nil)
    }
}

Then when you grab back the image from the UIImagePickerController, you only need to do the following to grab the coordinates :

let coordinate = (info[UIImagePickerControllerPHAsset] as? PHAsset)?.location?.coordinate