Abstraction and Intention

I came across a map of the US Interstate Highway system that got me thinking.  278theinterstatesystem.jpg
I used to teach a class at FIT covering digital product development and UI design. One of the topics covered the representation and abstraction of the physical (real)-world. To make information usable, some level of abstraction is almost always necessary - especially online, where limited screen sizes, the flattening of information, and issues of interaction intrude. All of these issues exist with printed matter, but there have been 450 years to work them out in a relatively stable medium.  To get the class thinking, I showed images of the London Underground map and how the representation of distance and location of stops were abstracted to enhance usability. For example, the incredibly condensed central core of the system is represented as being much larger than it really is, while far-flung stops are brought in closer. Harry Beck pioneered this representation, and it is covered nicely in a book and online.  The class got this and were nominally engaged (and supportive of the concept), but when I showed Massimo Vignelli's maps of the NYC Metro they responded much differently. I think because it hit home, they were much more opposed to losing an accurate geographic mapping of the subway system. This was the opposite of what I anticipated, as I figured they would appreciate being able to accurately and easily find a route or stop and already knew the physical dimensions of the city.Like so many patterns around us, the subway map that New Yorkers have is an evolved, hybrid approach to the problem. There still isn't a completely accurate geographic representation, but it is close enough to be useful in situations where someone might not know the area. Useful detail, however, is often obscured or inconsistent (how express trains work, for example). I'm pretty sure the highway map above is significantly less useful in this form given how people use highway maps. A strong knowledge of  US geography is helpful when looking at this, but even still, a quick glance shows clustering, density, and orientation trends that the loss of noise from a traditional map brings. The abstraction does open up thinking to a system level, which is probably something few people do outside of the DOT. On this level, overlays of population density, usage, capital outlays, infrastructure age, demographics, and many others can take on new meaning.Like any map, the loss of information opens new interpretations and limits others.