I believe when the NYC subway tried that they did have both.
I think what this misses, at least as far as Manhattan is concerned, is the grid system that already exists. Once you understand the grid, and the relationship between the subway system and the grid, then knowing the subway map is as good as knowing the geographic map and vice versa.
The first time I visited NYC was in 2004 before our handheld map systems. It took me all of 15 minutes to know exactly where I needed to go and how to get there without ever looking at a map, because my friend explained the system to me.
A map that divorces the geographic and subway systems simply leads to the necessity of learning 2 different things that are very intrinsically related, and in the case of Manhattan can actually substitute for each other.
I think what this misses, at least as far as Manhattan is concerned, is the grid system that already exists. Once you understand the grid, and the relationship between the subway system and the grid, then knowing the subway map is as good as knowing the geographic map and vice versa.
The first time I visited NYC was in 2004 before our handheld map systems. It took me all of 15 minutes to know exactly where I needed to go and how to get there without ever looking at a map, because my friend explained the system to me.
A map that divorces the geographic and subway systems simply leads to the necessity of learning 2 different things that are very intrinsically related, and in the case of Manhattan can actually substitute for each other.