Did you mean "geography"?
I agree, it would be very interesting to have the topologies of hilly areas like Seattle and SF taken into account in the sim. Let's say you set off your nuke over Elliot Bay. Or in a shipping container down on the south end. I wonder if the neighborhoods on the lee side of the central ridge separating the city from the lake would be spared in any big way. Places like Mt. Baker, Leschi, Madison Park. I wonder if N. Queen Anne would be partially spared? It would be ironic if the aquaduct and the 99 bridge survived. Similarly, I wonder if the blast effects would be channeled by the hills, perhaps down the Rainier valley for example.
It would be tragic, a lot of good pubs would be ruined even by a low-yield device.