Yes more symbols! A uncovered half-track, then one with the 3 American soldiers shooting from it. (a "The Dirty Dozen" reference)

A thought, coming in to this late, is to check the flavor text in the Mistborn books by Brandon Sanderson. Which may point to some detail things to through in.

Volcanic dust on roofs, and roads for example.

I found this web site with a series of aerial and satellite imagery. I thought it would be of interest.

I have seen 1600s maps of Port Royal that show turtle pens that look similar to your pens. If you were to add some big turtles in the water that might work.

Also posted a map of the "Spinward Marches" made using the Cosmographer's Traveller data importer. I have added trade volume data to it.

I put it in a "misc" Gallery.