Makes undiscovered areas easier to spot!

Now you will be able to see unexplored areas as black.

For example: sand displays as bright yellow on a map and unexplored areas displays as bright yellow too. So while mapping the desert or ocean you have a high chance of missing a pixel and it will be almost impossible to spot until you put in into an item frame because it blends in with the desert or looks like a small island on a scaled map. There are two unexplored pixels on the first image.

 Can you see them?

No? Maybe try on the second one.