MacGyver Season 1 Episode 14 Science Notes: Fish Scaler

Isn’t it nice that I have written enough of these MacGyver science note posts that I no longer have to give some witty introductory comment? Oh, I guess that was an intro comment. OK-next time it’s just going to jump into the science.

Picture triangulation

MacGyver is trying to track down some dude. He finds a skyline picture that he drew and assumes the guy drew it from his apartment window (somewhere in Atlanta).

Oh wait! I think I can find out where this guy lives based on the drawing. True? Yes, this is true. If the guy drew a scale drawing, then yes-it’s entirely possible to find out where he drew it from. Oh, if he does an abstract drawing then all bets are off. Right?

There is a lot here, so let me go over two important ideas needed to backwards engineer this drawing.

First-angular size. You already know about angular size. The farther away something gets, the smaller it looks. If you like, you can make it so that someones head appears to be as big as your thumb. Yes, the human would have to be much farther away than your thumb (from your eye).

If the thumb covers up someone’s head, then the two objects would have the same angular size. How about a diagram to explain angular size? Suppose some object has a length of L and is a distance r away from an observer. It might look like this.