If a cartographer fails the make a map test, handle it like any other failure with a condition or twist. Like Jared was saying, if you go with a twist, a good (evil) one is that whole map is inaccurate. If they use it, then they could get lost or end up somewhere else (per the GM’s discretion).
Or, you could just say that the cartographer is angry or exhausted from the ordeal, and the map is perfect.
If the cartographer was adding onto an existing map, you still have the choice to apply a twist or condition for a failure.
As the twist, a suggested failure could be the whole map is suspect because of the changes.
A different twist might play off the narration from the players. For example, because the Scholar was “helping” (but the passed helper die didn’t generate a success), the scholar’s inkwell and supplies he lent to the cartographer spilled over a portion of the map. The GM worked in the fact that the helper didn’t actually help. Part of the map is ruined, and now the map only gets you to the inn along the road instead of all the way to the other dungeon. Not as evil or as common of a twist, but it fit the fiction for the situation.
Or, give a condition and the map is still fine.
No, the GM doesn’t do anything with the player’s map. The GM has a separate “for GM’s-eyes only” map the players never see.
At the table or in the virtual tabletop apps, each player will make the map a little differently.
The player is responsible for recording area names and making maps. For new players, I will remind the cartographer a couple of times to jot down some name for the chamber when entering a new area because it does take some getting used to.
In Roll20, there is a text tool you can use to list the rooms or areas. You can put the text right onto screen so the other players can help the cartographer remember.
You can also use handouts in Roll20 to mark the maps you have successfully made. Your cartographer could edit the handout, re-name the title “Map: Skogenby to 3S,” and then jot down some notes indicating map was good from one door of the dungeon to the other.
Or, if you are playing at a real tabletop, use index cards as a quick way to record maps.
In Roll20, the text tool allows you to use different colors and text symbols to mark which rooms have been mapped or explored. Your room list could look like this:
- Camp in forest
- Path to Ruins
- Rat-Infested Rotunda (Exits: A*, B)
- Wine Cellar (Exits: A*, C, stairs*)
- Stinky Catacombs (Exits: Stairs*, D, E*, F)
- Prison Chambers (Exits: E*)
Then, you might make a map from the “Prison Chamber to the Lobby” to get all the way out of the dungeon.