So I still think your dog example is too complicated. All you need to know is if there's a 4 legged creature walking around. You can probably differentiate a cat from a dog here. You can also probably differentiate a small, medium, or large dog. You don't need to know the exact type for this data to be incredibly useful. Just knowing the size will get you a lot of useful data. It is really easy to over complicate the situation. A little data goes a long way.