Currently I'm working on a historical map of Seattle. I've already completed a detailed map of Downtown Seattle. I hope to finish the district map and an overview of the Pacific Northwest this week. As a basis for the maps I've used today's maps of OpenStreetmap. I used the Seattle Sourcebook to insert the locations and to compare the roads today with those 2050. The final poster should be in the format DIN A1 (841 x 594 mm / 23.39 x 33.11 inch). Here you can take a look at the production steps:
Early poster layout. In the top left corner is the placeholder for the Downtown road map and the Pacific Northwest overview.
Closeup photo, still without locations and street names.
Finished Downtown street map as a stand alone DIN A3 poster (210 x 297 mm / 11.69 x 16.54 inch)
Closeup photos of Downtown Seattle.
If you want to take a closer look to Downtown Seattle map you can download the slimmed PDF.