In 2009, shortly after I started carrying an iPhone, I caught myself with a funny new automatic habit. I would be at the large Fred Meyer grocery store near my home. Sometimes when I didn’t know where a product was, I would notice a brief impulse to reach for my phone. A few times I remember actually reaching for my pocket to pull it out. I never did get as far as entering “peanut butter” into the Maps application. But the habit impressed on me how accustomed I had become to using my phone to navigate in a new city. I turned to it instinctively for help with spatial navigation.
As silly as this habit seemed, I knew that one day my phone would become useful for indoor navigation. Indeed, recently Google announced Google Maps for Android mobile phones version 6.0 includes an indoor maps feature. You can read more about this at the Google LatLon blog.
Currently, indoor maps are available for major airports, and some major malls and large retailers. No transit stations are included. However, Google allows people to upload interior diagrams of buildings. If you want to see a transit station included, upload a map.
UPDATE (14-Dec-2011): Brian Ferris pointed out that interior maps are already available for some transit stations in Japan. Here’s the list of available interior maps.