A 1.10 remake of the abandoned biome mapping tool Pioneer Terrain Survey, should work with all Forge mods adding biomes. Recommended to run on a client not server, during the generation the game will freeze!
/gmb <mapname> [<scale> <radius>] [<centrex> <centrez>]
Scale can be either 1 or 2, defaults to center on your player position with a 1:1 scale and 512 block radius.