The industry is still fragmented and works in silos, except for Microsoft and Nokia where Nokia is providing its Destination Maps to Microsoft Bing Maps. Also, some consolidation or aggregation is expected to take place as only some of the players are specializing in particular verticals (i.e. Retail, Museums). Below is our take on the number of indoor maps each company has, including Google, Nokia, aisle411, Micello, and Point Inside. Retail maps are for venues such as Walgreens, Home Depot, and similar.
wrote about this back in 2010. In addition to malls and airports, Nokia is also mapping out stadiums and amusement parks.