Imagine a satellite blow-up of a city on mosaic, 1:10,000 scale. It'll take up most of a decent interior wall, so stand well back. There are certain obvious things you can tell at a glance. Is it a planned development or did it grow organically, responding to centuries of differing demand? Is it or was it ever fortified? Does it have a seaboard? Look closer, and you can learn more. Where the major thoroughfares are likely to be, if there is an IP shuttle port, if the city has parks. You can maybe, if you're a trained cartographer, even tell a little about the movements of the inhabitants. Where the desirable areas of town are, what the traffic problems are likely to be and if the city has suffered any serious bomb damage or riots recently.