Add Gps Metadata Dictionary to Image Taken with Avfoundation in Swift

How do I include location data using AVCapturePhoto?

I haven't dealt with the new IOS 11 AVCapturePhoto object so this answer has to make a couple of assumptions about how to access data but in theory all of this should work.

Before adding location data you need to ask the user if you can use their location. Add the "Privacy - Location When In Use" tag to your Info.plist. Then add the following code somewhere in your initialisation.

// Request authorization for location manager 
switch CLLocationManager.authorizationStatus() {
case .authorizedWhenInUse:
    break

case .notDetermined:
    locationManager.requestWhenInUseAuthorization()
    locationManagerStatus = CLLocationManager.authorizationStatus()

default:
    locationManagerStatus = .denied
}

Now the following will create a dictionary with location information in it.

// create GPS metadata properties
func createLocationMetadata() -> NSMutableDictionary? {

    guard CLLocationManager.authorizationStatus() == .authorizedWhenInUse else {return nil}

    if let location = locationManager.location {
        let gpsDictionary = NSMutableDictionary()
        var latitude = location.coordinate.latitude
        var longitude = location.coordinate.longitude
        var altitude = location.altitude
        var latitudeRef = "N"
        var longitudeRef = "E"
        var altitudeRef = 0

        if latitude < 0.0 {
            latitude = -latitude
            latitudeRef = "S"
        }

        if longitude < 0.0 {
            longitude = -longitude
            longitudeRef = "W"
        }

        if altitude < 0.0 {
            altitude = -altitude
            altitudeRef = 1
        }

        let formatter = DateFormatter()
        formatter.dateFormat = "yyyy:MM:dd"
        gpsDictionary[kCGImagePropertyGPSDateStamp] = formatter.string(from:location.timestamp)
        formatter.dateFormat = "HH:mm:ss"
        gpsDictionary[kCGImagePropertyGPSTimeStamp] = formatter.string(from:location.timestamp)
        gpsDictionary[kCGImagePropertyGPSLatitudeRef] = latitudeRef
        gpsDictionary[kCGImagePropertyGPSLatitude] = latitude
        gpsDictionary[kCGImagePropertyGPSLongitudeRef] = longitudeRef
        gpsDictionary[kCGImagePropertyGPSLongitude] = longitude
        gpsDictionary[kCGImagePropertyGPSDOP] = location.horizontalAccuracy
        gpsDictionary[kCGImagePropertyGPSAltitudeRef] = altitudeRef
        gpsDictionary[kCGImagePropertyGPSAltitude] = altitude

        if let heading = locationManager.heading {
            gpsDictionary[kCGImagePropertyGPSImgDirectionRef] = "T"
            gpsDictionary[kCGImagePropertyGPSImgDirection] = heading.trueHeading
        }

        return gpsDictionary;
    }
    return nil
}

This is where I have to do some guessing as I haven't dealt with IOS 11 AVPhotoCapture. You will need a file data representation of your image data. I assume

AVCapturePhoto.fileDataRepresentation() 

returns this. Also you will need the original file metadata. I'll take a guess that

AVCapturePhoto.metadata

contains this. With those assumptions the following function will give you a file data representation with additional location data. There may be newer IOS 11 methods to do this in a cleaner way.

func getFileRepresentationWithLocationData(photo : AVCapturePhoto) -> Data {
    // get image metadata
    var properties = photo.metadata

    // add gps data to metadata
    if let gpsDictionary = createLocationMetadata() {
        properties[kCGImagePropertyGPSDictionary as String] = gpsDictionary
    }

    // create new file representation with edited metadata
    return photo.fileDataRepresentation(withReplacementMetadata:properties,
        replacementEmbeddedThumbnailPhotoFormat:photo.embeddedThumbnailPhotoFormat,
        replacementEmbeddedThumbnailPixelBuffer:photo.previewPixelBuffer,
        replacementDepthData:photo.depthData)
}

Access GPS coordinates from metadata dictionary

I order for the image to have the location, the location service must be active. Then with the following code you can get its coordinates when they exist.

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)")
        }
    }
}

Hope it helps.

From Christian
https://stackoverflow.com/a/26842206/2269679

Save CUSTOM metadata in an image taken from AVFoundation in iOS

UIImage and CIImage don't hold all the metadata. In fact, converting it from NSData to either of those two formats will strip a lot of that metadata out, so IMHO, UIImage and CIImage should only be used if you are planning on displaying it in the UI or passing it to CoreImage.

You can read the image properties like this:

- (NSDictionary *)getImageProperties:(NSData *)imageData {
    // get the original image metadata
    CGImageSourceRef imageSourceRef = CGImageSourceCreateWithData((__bridge CFDataRef) imageData, NULL);
    CFDictionaryRef properties = CGImageSourceCopyPropertiesAtIndex(imageSourceRef, 0, NULL);
    NSDictionary *props = (__bridge_transfer NSDictionary *) properties;
    CFRelease(imageSourceRef);

    return props;
}

You can then convert your NSDictionary to a NSMutableDictionary:

NSDictionary *props = [self getImageProperties:imageData];
NSMutableDictionary *mutableDictionary = [NSMutableDictionary dictionaryWithDictionary:props];

After that, add whatever fields you would like. Note that EXIF data is found by grabbing the kCGImagePropertyExifDictionary, GPS data by the kCGImagePropertyGPSDictionary, and so on:

NSMutableDictionary *exifDictionary = properties[(__bridge NSString *) kCGImagePropertyExifDictionary];

Look at the CGImageProperties header file for all the keys available.

Okay, so now that you have made whatever changes you needed to the metadata, adding it back takes a couple of more steps:

// incoming image data
NSData *imageData;

// create the image ref
CGDataProviderRef imgDataProvider = CGDataProviderCreateWithCFData((__bridge CFDataRef) imageData);
CGImageRef imageRef = CGImageCreateWithJPEGDataProvider(imgDataProvider, NULL, true, kCGRenderingIntentDefault);

// the updated properties from above
NSMutableDictionary *mutableDictionary;

// create the new output data
CFMutableDataRef newImageData = CFDataCreateMutable(NULL, 0);
// my code assumes JPEG type since the input is from the iOS device camera
CFStringRef type = UTTypeCreatePreferredIdentifierForTag(kUTTagClassMIMEType, (__bridge CFStringRef) @"image/jpg", kUTTypeImage);
// create the destination
CGImageDestinationRef destination = CGImageDestinationCreateWithData(newImageData, type, 1, NULL);
// add the image to the destination
CGImageDestinationAddImage(destination, imageRef, (__bridge CFDictionaryRef) mutableDictionary);
// finalize the write
CGImageDestinationFinalize(destination);

// memory cleanup
CGDataProviderRelease(imgDataProvider);
CGImageRelease(imageRef);
CFRelease(type);
CFRelease(destination);

// your new image data
NSData *newImage = (__bridge_transfer NSData *)newImageData;

And there you have it.

Write UIImage along with metadata (EXIF, GPS, TIFF) in iPhone's Photo library

The function: UIImageWriteToSavePhotosAlbum only writes the image data.

You need to read up on the ALAssetsLibrary

The method you ultimately want to call is:

 ALAssetsLibrary *library = [[ALAssetsLibrary alloc]
 [library writeImageToSavedPhotosAlbum:metadata:completionBlock];

How to write exif metadata to an image (not the camera roll, just a UIImage or JPEG)

UIImage does not contain metadata information (it is stripped). So if you want to save it without using the imagepicker method (not in camera roll):

Follow the answer here to write to a file with the metadata intact:

Problem setting exif data for an image

no idea why would this be downvoted but here is the method:

In this case im getting the image through AVFoundation and this is what goes in the

[[self stillImageOutput] captureStillImageAsynchronouslyFromConnection:videoConnection 
                                                     completionHandler:^(CMSampleBufferRef imageSampleBuffer, NSError *error) 
{
    // code here
}

block code:

    CFDictionaryRef metaDict = CMCopyDictionaryOfAttachments(NULL, imageSampleBuffer, kCMAttachmentMode_ShouldPropagate);

    CFMutableDictionaryRef mutable = CFDictionaryCreateMutableCopy(NULL, 0, metaDict);

    // 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(loc.coordinate.latitude)], kCGImagePropertyGPSLatitude
                               , ((loc.coordinate.latitude >= 0) ? @"N" : @"S"), kCGImagePropertyGPSLatitudeRef
                               , [NSNumber numberWithFloat:fabs(loc.coordinate.longitude)], kCGImagePropertyGPSLongitude
                               , ((loc.coordinate.longitude >= 0) ? @"E" : @"W"), kCGImagePropertyGPSLongitudeRef
                               , [formatter stringFromDate:[loc timestamp]], kCGImagePropertyGPSTimeStamp
                               , [NSNumber numberWithFloat:fabs(loc.altitude)], kCGImagePropertyGPSAltitude
                               , nil];  

    // The gps info goes into the gps metadata part

    CFDictionarySetValue(mutable, kCGImagePropertyGPSDictionary, (__bridge void *)gpsDict);

    // Here just as an example im adding the attitude matrix in the exif comment metadata

    CMRotationMatrix m = att.rotationMatrix;
    GLKMatrix4 attMat = GLKMatrix4Make(m.m11, m.m12, m.m13, 0, m.m21, m.m22, m.m23, 0, m.m31, m.m32, m.m33, 0, 0, 0, 0, 1);

    NSMutableDictionary *EXIFDictionary = (__bridge NSMutableDictionary*)CFDictionaryGetValue(mutable, kCGImagePropertyExifDictionary);

    [EXIFDictionary setValue:NSStringFromGLKMatrix4(attMat) forKey:(NSString *)kCGImagePropertyExifUserComment];

    CFDictionarySetValue(mutable, kCGImagePropertyExifDictionary, (__bridge void *)EXIFDictionary);

    NSData *jpeg = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageSampleBuffer] ;

After this code you will have your image in the jpeg nsdata and the correspoding dictionary for that image in the mutable cfdictionary.

All you have to do now is:

    CGImageSourceRef source = CGImageSourceCreateWithData((__bridge CFDataRef)jpeg, NULL);

    CFStringRef UTI = CGImageSourceGetType(source); //this is the type of image (e.g., public.jpeg)

    NSMutableData *dest_data = [NSMutableData data];

    CGImageDestinationRef destination = CGImageDestinationCreateWithData((__bridge CFMutableDataRef)dest_data,UTI,1,NULL);

    if(!destination) {
        NSLog(@"***Could not create image destination ***");
    }

    //add the image contained in the image source to the destination, overidding the old metadata with our modified metadata
    CGImageDestinationAddImageFromSource(destination,source,0, (CFDictionaryRef) mutable);

    //tell the destination to write the image data and metadata into our data object.
    //It will return false if something goes wrong
    BOOL success = CGImageDestinationFinalize(destination);

    if(!success) {
        NSLog(@"***Could not create data from image destination ***");
    }

    //now we have the data ready to go, so do whatever you want with it
    //here we just write it to disk at the same path we were passed

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
    NSString *documentsDirectory = [paths objectAtIndex:0]; // Get documents folder
    NSString *dataPath = [documentsDirectory stringByAppendingPathComponent:@"ImagesFolder"];

    NSError *error;
    if (![[NSFileManager defaultManager] fileExistsAtPath:dataPath])
        [[NSFileManager defaultManager] createDirectoryAtPath:dataPath withIntermediateDirectories:NO attributes:nil error:&error]; //Create folder

    //    NSString *imageName = @"ImageName";

    NSString *fullPath = [dataPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.jpg", name]]; //add our image to the path

    [dest_data writeToFile:fullPath atomically:YES];

    //cleanup

    CFRelease(destination);
    CFRelease(source);

Note how I'm not saving using the ALAssets but directly into a folder of my choice.

Btw most of this code can be found in the link I posted at first.

Problem setting exif data for an image

The following blog post is where I got my answer when I had issues with modifying and saving Exif data Caffeinated Cocoa. This works on iOS.

Here is my test code for writing Exif and GPS data. It pretty much a copy and paste of the code from the above blog. I am using this to write exif data to a captured image.

NSData *jpeg = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer] ;

CGImageSourceRef  source ;
    source = CGImageSourceCreateWithData((CFDataRef)jpeg, NULL);

    //get all the metadata in the image
    NSDictionary *metadata = (NSDictionary *) CGImageSourceCopyPropertiesAtIndex(source,0,NULL);

    //make the metadata dictionary mutable so we can add properties to it
    NSMutableDictionary *metadataAsMutable = [[metadata mutableCopy]autorelease];
    [metadata release];

    NSMutableDictionary *EXIFDictionary = [[[metadataAsMutable objectForKey:(NSString *)kCGImagePropertyExifDictionary]mutableCopy]autorelease];
    NSMutableDictionary *GPSDictionary = [[[metadataAsMutable objectForKey:(NSString *)kCGImagePropertyGPSDictionary]mutableCopy]autorelease];
    if(!EXIFDictionary) {
        //if the image does not have an EXIF dictionary (not all images do), then create one for us to use
        EXIFDictionary = [NSMutableDictionary dictionary];
    }
    if(!GPSDictionary) {
        GPSDictionary = [NSMutableDictionary dictionary];
    }

    //Setup GPS dict

    [GPSDictionary setValue:[NSNumber numberWithFloat:_lat] forKey:(NSString*)kCGImagePropertyGPSLatitude];
    [GPSDictionary setValue:[NSNumber numberWithFloat:_lon] forKey:(NSString*)kCGImagePropertyGPSLongitude];
    [GPSDictionary setValue:lat_ref forKey:(NSString*)kCGImagePropertyGPSLatitudeRef];
    [GPSDictionary setValue:lon_ref forKey:(NSString*)kCGImagePropertyGPSLongitudeRef];
    [GPSDictionary setValue:[NSNumber numberWithFloat:_alt] forKey:(NSString*)kCGImagePropertyGPSAltitude];
    [GPSDictionary setValue:[NSNumber numberWithShort:alt_ref] forKey:(NSString*)kCGImagePropertyGPSAltitudeRef]; 
    [GPSDictionary setValue:[NSNumber numberWithFloat:_heading] forKey:(NSString*)kCGImagePropertyGPSImgDirection];
    [GPSDictionary setValue:[NSString stringWithFormat:@"%c",_headingRef] forKey:(NSString*)kCGImagePropertyGPSImgDirectionRef];

    [EXIFDictionary setValue:xml forKey:(NSString *)kCGImagePropertyExifUserComment];
    //add our modified EXIF data back into the image’s metadata
    [metadataAsMutable setObject:EXIFDictionary forKey:(NSString *)kCGImagePropertyExifDictionary];
    [metadataAsMutable setObject:GPSDictionary forKey:(NSString *)kCGImagePropertyGPSDictionary];

    CFStringRef UTI = CGImageSourceGetType(source); //this is the type of image (e.g., public.jpeg)

    //this will be the data CGImageDestinationRef will write into
    NSMutableData *dest_data = [NSMutableData data];

    CGImageDestinationRef destination = CGImageDestinationCreateWithData((CFMutableDataRef)dest_data,UTI,1,NULL);

    if(!destination) {
        NSLog(@"***Could not create image destination ***");
    }

    //add the image contained in the image source to the destination, overidding the old metadata with our modified metadata
    CGImageDestinationAddImageFromSource(destination,source,0, (CFDictionaryRef) metadataAsMutable);

    //tell the destination to write the image data and metadata into our data object.
    //It will return false if something goes wrong
    BOOL success = NO;
    success = CGImageDestinationFinalize(destination);

    if(!success) {
        NSLog(@"***Could not create data from image destination ***");
    }

    //now we have the data ready to go, so do whatever you want with it
    //here we just write it to disk at the same path we were passed
    [dest_data writeToFile:file atomically:YES];

    //cleanup

    CFRelease(destination);
    CFRelease(source);

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