I stumbled across this web site this morning before having my morning coffee! What a find. It’s an interactive map of 1748 Rome by Giambattista Nolli, an Italian architect and surveyor, created by the University of Oregon under the advisory of Jim Tice, University of Oregon, Dept of Architecture and Erik Steiner, InfoGraphics Lab, Dept of Geography (there are further contributors – check out the Preface page for more information).
Activate the map by clicking on the box that says “Launch Map Engine” on the right hand side. I haven’t had a chance to explore the site fully but it seems like a rich find if you are interested in historical Rome.
You can read more about the project here.
There’s also an excellent bibliography and further links.