These are roadmaps about how to get somewhere, but the map is not the terrain, and there are a few parts that are known to only be 90% mapped. That doesn't say

These are roadmaps about how to get somewhere, but the map is not the terrain, and there are a few parts that are known to only be 90% mapped. That doesn't say that the 10% unmapped contains an impassable cliff or easily crossable plains, but we will likely find out.