Mapping and Caving: A Compromise

I was working on adding general proficiency selection to the henchinator today, and in the process ended up re-reading parts of the Proficiencies chapter.  There I once again encountered my old enemies, Mapping and Caving.  I like mapping as a player, and I like having my players make maps.  As a result, the ability to "map an area by memory" is sort of annoying - it kills off that part of gameplay (and that artifacts that generate it) that I enjoy.  Previously, I've soft-banned these proficiencies, but upon further consideration, I think a compromise is possible.

Mapping continues to permit an illiterate character to map for the party.  In addition, on a throw of 11+, he can produce an accurate copy from memory of a map he has studied or which he created, though doing so takes an amount of time varying with the size and complexity of the map.  This provides insurance against threats which destroy the party's map within the game world - water, burning oil, losing the guy who usually does the mapping - but permits the players to continue to use their map even in the event of such destruction.  Likewise, caving permits a party to retrace their way out of a dungeon or cave when their map has been destroyed, but without the necessity of taking time to sit down in the dungeon and let the mapper re-scribble from memory on a piece of parchment.

And speaking of maps (with apologies to people who actually art)...