Oh! That's a good tip. I have been omitting room numbers on player versions, figuring the players could just point to the room they have a question about, but that could be tricky in a large map like this. Good suggestion.

In a different thread, @Ricko was asking for advice on how mappers approach adding numeric labels on a map:

I thought I would add my two cents in a new thread for the topic, to make the discussion easier to find later.

I am certainly no expert on the matter, but when I am labeling things, I try to think of how it would be presented in a purchased campaign supplement. I try to make it flow in the order the party would be traveling, starting with #1 at the entrance and flowing from there to where they'd go next.

Of course, the party may have choices on which direction to go, so there may not be an obvious answer for what comes next after they enter. I just pick one direction and try to label things as contiguously as possible, clustering the numbering as best I can. So it's not necessarily clockwise, or left to right, or up or down -- it's just the route the way things the adventurers may go.

With cities and towns, it can vary. Sometimes I pick a road or city gate where the party may enter the city and then flow from there. Other times, I may start in a central area like a market square or town hall as the starting point. My numbering also clusters (like, every shop around a town square gets numbered before moving to the next area), and go neighborhood by neighborhood.

For overland maps...to be honest, I've never numbered overland maps. I've only used text labels, where it isn't the same issue.

I'd love to hear other people's ideas for how they approach.

Don't worry about the layer it's on, the sheet it's on is more important. It will put it on the Grid sheet and that can be moved, and it's placement will determine how things are rendered. If your land renders before the sea (appears higher in the order of sheets), you can put the Grid sheet in between.

If the sea renders before the land, there are other tricks I can suggest, like maybe a color key cutout (have to think through that), but others may have ideas.