Scene size in Xcode 6 / SpriteKit / Swift

I've been getting stuck doing what should be really simple stuff in Xcode, I am trying to add a sprite to the scene and for it to sit in the bottom left corner:

var groundTexture : SKTexture = SKTexture(imageNamed: "dirt-block")    
var ground : SKSpriteNode = SKSpriteNode(texture: groundTexture)
ground.position = CGPointMake(ground.size.width/2, ground.size.height/2)
self.addChild(ground)

This doesn't show anything, so I took a look at what the scene dimensions are and self.frame.size.width and self.frame.size.height are returning a width of 1024 and a height of 768, regardless of orientation.

I want this fixed in landscape mode if that makes any difference to the answer?

I'm obviously missing a very fundamental idea to do with setting up the scene, if anybody could shed any light it would be much appreciated.

Thanks.

Alexander Wohltan

You have to edit the GameViewController:

Cut everything from viewDidLoad() except super.viewDidLoad()

Overwrite viewWillLayoutSubviews

override func viewWillLayoutSubviews() {
    super.viewWillLayoutSubviews()

    if let scene = GameScene.unarchiveFromFile("GameScene") as? GameScene {
        // Configure the view.
        var skView = self.view as SKView
        skView.showsFPS = true
        skView.showsNodeCount = true

        /* Sprite Kit applies additional optimizations to improve rendering performance */
        skView.ignoresSiblingOrder = true

        /* Set the scale mode to scale to fit the window */
        scene.size = skView.bounds.size
        scene.scaleMode = .AspectFill

        skView.presentScene(scene)
    }
}

Also you should set the scene size as you can see