为自定义相机拍摄的UIImage添加GPS数据失败，求排查

你的代码核心问题出在最后把带GPS元数据的Data转成UIImage这一步——UIImage对象本身并不存储EXIF、GPS这类图片元数据，它只包含像素和基础显示信息。所以当你把mutableData转成UIImage后，之前添加的GPS元数据会直接丢失，后续保存这个UIImage到相册自然没有位置信息。

修正方案 #

直接使用包含GPS元数据的Data来保存到相册，不要经过UIImage中转。调整代码逻辑如下：

1. 修改函数返回带元数据的Data #

把原函数的返回类型从UIImage改成Data，直接返回包含GPS信息的图片数据：

func addLocationToImageData(image: UIImage, location: CLLocation) throws -> Data {
    guard let data = image.jpegData(compressionQuality: 1.0) else {
        throw NSError(domain: "error", code: 0, userInfo: [NSLocalizedDescriptionKey: "Failed to get JPEG data from image."])
    }

    let metadata = NSMutableDictionary()
    let gpsDict = NSMutableDictionary()

    let latitude = location.coordinate.latitude
    let longitude = location.coordinate.longitude

    // 写入GPS核心坐标信息
    gpsDict[(kCGImagePropertyGPSLatitude as String)] = abs(latitude)
    gpsDict[(kCGImagePropertyGPSLatitudeRef as String)] = latitude < 0.0 ? "S" : "N"
    gpsDict[(kCGImagePropertyGPSLongitude as String)] = abs(longitude)
    gpsDict[(kCGImagePropertyGPSLongitudeRef as String)] = longitude < 0.0 ? "W" : "E"
    // 可选：补充拍摄时间戳，让元数据更完整
    gpsDict[(kCGImagePropertyGPSTimeStamp as String)] = location.timestamp
    gpsDict[(kCGImagePropertyGPSDateStamp as String)] = ISO8601DateFormatter().string(from: location.timestamp)

    metadata[(kCGImagePropertyGPSDictionary as String)] = gpsDict

    guard let source = CGImageSourceCreateWithData(data as CFData, nil) else {
        throw NSError(domain: "error", code: 0, userInfo: [NSLocalizedDescriptionKey: "Failed to create image source from data."])
    }

    let uti = CGImageSourceGetType(source)!
    let mutableData = NSMutableData(data: data)

    guard let destination = CGImageDestinationCreateWithData(mutableData, uti, 1, nil) else {
        throw NSError(domain: "error", code: 0, userInfo: [NSLocalizedDescriptionKey: "Failed to create image destination."])
    }

    CGImageDestinationAddImageFromSource(destination, source, 0, metadata)

    guard CGImageDestinationFinalize(destination) else {
        throw NSError(domain: "error", code: 0, userInfo: [NSLocalizedDescriptionKey: "Failed to write image with metadata to data."])
    }

    return mutableData as Data
}

2. 直接保存Data到相册 #

调用上述函数得到带元数据的Data后，用PHAssetCreationRequest保存，确保元数据被完整保留：

import Photos

// 假设你已经获取到拍摄的image和当前location
do {
    let imageDataWithGPS = try addLocationToImageData(image: capturedImage, location: currentLocation)
    
    PHPhotoLibrary.requestAuthorization { status in
        guard status == .authorized else { return }
        
        PHPhotoLibrary.shared().performChanges({
            let creationRequest = PHAssetCreationRequest.forAsset()
            creationRequest.addResource(with: .photo, data: imageDataWithGPS, options: nil)
        }) { success, error in
            if let error = error {
                print("保存失败：\(error.localizedDescription)")
            } else {
                print("图片带位置信息保存成功")
            }
        }
    }
} catch {
    print("添加位置信息失败：\(error.localizedDescription)")
}

额外排查点 #

• 确认App已获取精确位置权限，Info.plist中需配置NSLocationWhenInUseUsageDescription或NSLocationAlwaysAndWhenInUseUsageDescription
• 如果原图片是PNG格式，可将jpegData替换为pngData()，但同样要通过Data保存，不能转成UIImage后再存储
• 保存后可通过Mac预览的「显示检查器」查看图片元数据，确认GPS信息是否存在

内容的提问来源于stack exchange，提问作者David