I agree with Rik pretty much. You can describe the layout (mostly mountains/plains, direction of rivers, location based on other stuff - NW of that mountain is a stack of units)...giving exact locations (3N and 2NW) is stretching it a bit, depends on how much of it you use.
Things that aren't allowed: giving a whole 'text map' (ie; N of that city is plains. It has a road and irrigation. NW is a mountain. It is mined with a railroad)... is NOT allowed, nor is a screenshot in any way until Navigation. Neither is creating a map in the editor and taking a screenshot of it.
When in doubt, just refer us to the plan and we'll give a ruling.