Dyeing maps

It would be nice to be able dye an empty map, filling it in entirely with the specified colour. This would save grinding for 16,000 concrete blocks just to have a blank map AND a 128x128 area to build the art - heavily cutting out a grind for an otherwise simple item.

This would either be done in a crafting table or a cartography table, though I'm not sure which would fit best as this isn't 'mapmaking' per se. If you really wanted to go the extra distance, they could be dyed the same way Leather Armor can be, mixing dyes to create any hex code needed.