Most of the 9,000 buildings in the Ptolus poster map are standard houses, warehouses, and so on. But many of them are special locations designed from the very outset to have a unique place on the city map that is also exactly reflected by their treatment in the book itself.

To begin the process, Monte draws a rough sketch of the location and sends it to Ed.

Some of the buildings of Ptolus were spec'd for particular locations on the city map. Others, like the observatory, could go almost anywhere within its home district.

To begin, Ed placed a tiny version of Monte's sketch of the observatory on the city map where the building will go.

As part of the process of designing the map of the observatory, Ed used all available resources, including the building artwork (at left, by The Forge Studios) and the detailed description that appears in the book.

(No larger version available.)

Next, Ed creates the version of the observatory that appears on the poster map. When he's done, he has a basic outline he can use for the building floor plans that go in the book itself.

Taking that outline, Ed expands it and then fills in walls, doors, and other features. In this case, he custom-drew the observatory's telescope as well.

Note that the ghosted-back buildings and pool in the background of the floor plans reflect the building's street position.

The final version of the map includes labels and, in many cases, furnishings.