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?
I found a solution using the following code:
if picker.sourceType == UIImagePickerControllerSourceType.PhotoLibrary
{
if let currentLat = pickedLat as CLLocationDegrees?
{
self.latitude = pickedLat!
self.longitude = pickedLong!
}
else
{
var library = ALAssetsLibrary()
library.enumerateGroupsWithTypes(ALAssetsGroupAll, usingBlock: { (group, stop) -> Void in
if (group != nil) {
println("Group is not nil")
println(group.valueForProperty(ALAssetsGroupPropertyName))
group.enumerateAssetsUsingBlock { (asset, index, stop) in
if asset != nil
{
if let location: CLLocation = asset.valueForProperty(ALAssetPropertyLocation) as CLLocation!
{ let lat = location.coordinate.latitude
let long = location.coordinate.longitude
self.latitude = lat
self.longitude = lat
println(lat)
println(long)
}
}
}
} else
{
println("The group is empty!")
}
})
{ (error) -> Void in
println("problem loading albums: \(error)")
}
}
}
What it does is that it reads the entire album and prints the location if the photo has that property, else it prints "location not found". It does so for every photo in the album.So I have another question... I want to display the location info just for the photo that I have selected, not for the entire album. Does anyone have a clue how this can be accomplished?
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