This does the following: Randomly generates a world, saves it as a chunk file, loads that chunk file for the player to see. You can set how far of a radius to load the chunk files. This is how you can have an infinite world map.
If you are looking for an updated version that has more features, check out my new Chunk project here: https://marketplace.gamemaker.io/assets/11795/world-chunks-infinite-map
End User Licence Agreement (EULA).