City sketches...

[timmae]

I am trying to track down some larger sketches (or posters, but really looking for sepias or originals) of city layouts. The kind I have in mind are of larger North American cities similar to a couple I had seen of Chicago at the Printers Row book fair this last summer. Yeah, I should have bought them then but oh well... Those ran around $100-150 for a copy of the original and showed the city proper. Most are done at an aerial vantage point roughly 20,000 feet up and looking from the Southeast (the ones I had seen of Chicago anyways). It could be done with chalks but I suspect pencil is probably more accurate. I remember seeing these sketches in libraries and public places, city ahlls and such. Any ideas on where a guy could find something like this??