Very interesting. We actually are looking at viable approaches to get usable indoor maps for large buildings currently. We are building map based productivity software for workers in factories and offices. Maps are important for our use case but not the core thing we do. We actually partner with other companies for maps and positioning typically.

Indoor mapping is a hard problem because typical map providers tend to ignore private spaces, which is where maps are most needed. E.g. Apple, Google, Here, etc have great maps for a very limited set of public buildings but they don't really have solutions for indoors.

We know of a few companies specializing in this but it typically involves a lot of manual work and tends to have a high cost, require a lot of hand holding, and some very niche mapping skills. Also, a lot of indoor maps are intended for e.g. architects, contain a lot of clutter, or are generally not well suited for use on e.g. mobile screens.

It's an interesting problem to start tackling because we are getting kind of a critical mass of technology that will be able to start delivering pretty accurate positioning to commodity phones. There are all sorts of things happening in the industry related to that. It's a bit similar to when GPS became common on phones and it became a mass market in a few short years. Before that you had all sorts of niche stuff. After that you had ridiculous amounts of user generated content, open street maps, foursquare, etc.