The map was done at a 1:1 scale. Karnov is a game where the screen can scroll up as well as left/right, by jumping. There are two items, the ladder and the high jump shoes (and in some later stages, you can fly with a wing item), which allowed me to take some of the screenshots at the top of the screen. The parts I was unable to reach with this method, I filled in with the dark blue background. There was also a small part of the second sewer pipe which is impossible to see in screen, so I had to borrow some pixels from the first pipe.
There are two possible codes which would make mapping the rest of this game much easier - the ability to use the wings at any point in the game, and infinite time before items expire. If there was the ability to change how high Karnov can jump (which might be possible, considering that there's an item in the game that lets you jump twice as high), that would also help. Unfortunately these codes have never been published, and it's been a LONG LONG time since I've used memory searching to figure out how to modify these, so any help would be greatly appreciated.