Larb makes a good point. There'd have to be a reason for so much open space between the buildings (as drawn) and the walls.
The walled cities of Germany and Italy are packed chock-a-block with buildings. The premium spots are city center (where all the business is conducted) and against the wall (where only 3 walls have to be built instead of four).
Maybe the open space is rubble from earlier iterations of the city's life?
Maybe the old walls fell, destroying much of the city. The survivors are now superstitious about living too close to the walls, used the rubble from old buildings to build new ones for the (now reduced) population?

But aren't we assuming things about the wall? What if it's more like a stone fence around a pasture, meant only to keep out snakes? I know of one town in California that has build a 2' wall around the town for that (claimed) reason...