Indoor mapping is already supported by Google and Bing.  Micello is in the business of creating indoor maps of major venues around the world.  Most of the activity seems to be focussed on consumers and locations such as malls, airports and department stores.  A typical indoor application would help you find particular products in a mall or department store.

The major problem that distinguishes indoor from outdoor location and mapping is that there is no widely recognized indoor equivalent of GPS.  When you are outside of buildings on most of the Earth’s surface you can use GPS  to determine where you, other people and things are.  As soon as you walk into a building, GPS no longer works and it is difficult to automatically track people and objects.  For example, to be able to track a firefighter in a building  that has not been prepared in advance remains a challenge.

There have been a number of attempts to solve this problem.  Wifi signals from transmitters with known locations can be used to triangulate locations to with an accuracy of 10-15 feet.  Other technologies involve tracking cell phone location by triangulation, RFID, accelerometers, or tracking by low frequency radio frequency waves that are not as affected by walls as high frequency waves.

Another challenge is 3D location in tall buildings, translating an elevation in meters or feet to a particular floor and vice versa.

The business benefit of indoor location is significant because it increases the value of your assets – when you can locate equipment and facilities easily, you will use them more.  In the case of hospitals it can be a matter of life and death to find the “crash cart” in seconds rather than minutes.

The Open Geospatial Consortium’s  IndoorGML Standards Working Group has released a candidate  IndoorGML Encoding Standard.  The  IndoorGML Encoding Standard has been developed to provide a common schema framework for interoperability between indoor spatial applications such as indoor location services, indoor web map services, indoor emergency control, guiding services for visually handicapped persons in indoor space, and indoor robotics. The IndoorGML Encoding Standard is intended to provide a cross-platform, vendor-neutral way of communicating indoor spatial information. The IndoorGML Standards Working Group worked in collaboration with other standards groups including ISO/TC204 and IEEE Robotics & Automation Society (RAS).

IndoorGML has been implemented as an application schema of the OGC Geographic Markup Language (GML) Version 3.2.1. IndoorGML’s set of geometric and semantic data elements intended to be iconsistent with other standards such as the OGC’s CityGML standard and buildingSMART’s Industry Foundation Classes (IFCs).

IndoorGML specifies conceptual models and XML schemas for

• Geometric and semantic properties of spaces and connectivity
• Navigation context and constraints
• Space subdivisions and types of connectivity between spaces
• Navigation networks (logical and metric) and their relationships

The OGC is requesting public comment for a month ending on March 21, 2014.  You can download the standard here.