They really are below the landmass.

The sheets are in the order in which they are rendered, which means the RIVERS sheet is rendered before the LAKES sheet, and both are rendered before the LAND sheet. Move the LAND sheet up to just underneath the NAVIGATION LINES sheet and you should be ok.

Two different views...

Since the same thing is happening on FB where I asked the same question, then at a guess I've got it about average, which is what I wanted. Some of the buildings might have more or less snow, just like in the photos we've seen above.

Something a bit like this, then... Or is this too melted to go with the thatch?

Oh shoot! I forgot to cut the chimney extent out of the map file, so its a lot brighter than it should be, but you get the general idea.

On the progress side (or lack of it today) I've had quite a struggle getting the gradient shading of the map file correct so that the hollows around the dormer look filled with snow, and everything the right size and shape to be the same as the original but with a layer of snow on it. Not sure how all this is going to work when I start combining them, but we'll see in the morning now.

@Shessar - I think you are probably right about the rafters, and thank you :) I think I remember a map you once did where you were trying to create a snowy scene not a lot unlike this one. Its been in the back of my mind for a while now ;)

@JimP - yes, that's definitely more of a spring theme than a winter one, but I know what you mean. Towards the end of the last inch of snow we had here it hung around in the shade for at least 2 weeks longer than it did in the sunny places.