Thank you Chashio. In reference to the bamboo: a previous map I did, I drew directly onto a bamboo sushi roller. I used felt markers and it was about 11"x14". Was having trouble with the bamboo sticks rolling (thus distorting the image), so I have picked up a few flat bamboo placemats to help with that on future pieces. It is posted in one of my albums.
I really like using alternative mediums lately (well I've always used grocery bags) but the bamboo and "sail" fragments have got the idea pot steaming.
On this one, as well as "Ming's lair" in my WIP album, are done with felt tip markers and measure in at 12"x17". For maps I do on paper, I use pencil, ink and oil pastel pencils.