I kinda shutter at the thought of trying to map a sewer system in a PBP forum.<br/><br/>"You see a 20' stretch of sewer ahead of you before the darkness makes it impossible to see futher. 10' ahead, a T section can be seen that leads ooff to the right, or south."<br/><br/>While it's not a big thing, mapping usually means that everyone wants to walk every square foot and it can loose the story plot as quickly as no GM as they wonder aimlessly about. As things go, we have some sense that we are going in the direction that the GM intends and are moving the story along at some pace.<br/><br/>I've seen some really bad mapping as a side note. A party I was in had a map so screwed up by the time that we found the place we wanted, no one could figure out how to get back because mistakes had been made and it became a maze of dead ends and "I think we've seen this puddle before, see the mold in the shape of "help?"