You can categorise cities in any multitude of ways, but asking whether they were designed by grid-obsessed city planners; or allowed to sprawl wilfully in every direction, is one place to start.
Grid-like order, or lack thereof, is pretty obvious when you look at a city's street map, but a data researcher has made the job even easier by adding colour. Sephen von Worley, an artist and scientist, chose a series of colours to represent different grid orientations, then applied them algorithmically to maps of five US cities and five others from around the world.
The method allows you to see which cities are broadly grid-based, even where the grid occasionally changes direction. Here's New York City, with its delightfully regular street patterns:
In general, the US cities have more rigid street systems than other world cities - in general, that's because they were built more recently and more quicky. Paris, on the other hand...
Boston is the least orderly of the US cities: the city's streets are older, and are famously harder to navigate than other, newer US cities. However, this colouration shows that sections of the city have their own, internally consistent grid systems:
Especially when compared to European cities, it's less sprawling than it seems.
You can see the rest of the maps at von Worley's data visualisation site.