Think I've got it now.

A reedbed isn't as dense as it looks from the side. You can see the mud between the stems in overhead photographs, which means I can use Symbols in Area and allow sufficient spacing to keep the number of symbols down just a bit.

And there will be burnt out buildings as well, if there is time.

This evening, though, I got distracted by the idea of reed beds for the marshy/boggy/swampy areas that were requested. Not quite there, but close, I think

I've turned it into a bonfire and made some other fires for other kinds of things.

There will be smoke as well - when I am happy with the look of it.

That's really interesting Calibre! It's nothing like the image I've been building in my own imagination.

I can see this is going to be quite a prolonged project.

Thanks Remy. I didn't know it worked with imported images as well as symbols.

That will cut out a lot of fiddling around, since I looked back more carefully at my own parchment-added maps and realised that they were either seamless parchment fills from PF assets, or I had deliberately imported the parchment as a bitmap fill and drawn a rectangle of it over the map. That last option is the fiddly one, since you have to scale it right to move the non-seamless joins off the edge of the map in both directions.