Minecraft wiki entry for Map, associated text: While maps in the Nether work, they show only the red-and-gray pattern, regardless of the blocks placed. The only useful function is finding where the player is in relation to placed framed maps, which show as green pointers. Additionally, the player pointer rapidly spins and is not a good indicator of direction. Placing a banner in the Nether still shows it on the map as usual. Having a smaller map image while riding a strider in the Nether can help one to see one's footing while traveling over lava.