This SBIR Phase II project will develop software and a system that enables nearly automatic generation and maintenance of a global database of indoor maps through crowdsourcing and data fusion. The current state of the art in indoor mapping relies on a manual labor-intensive process to create and maintain maps as they change over time, which is difficult to scale. A dynamic map-building system will address the challenge of generating and updating key indoor map navigation data. The developed mapping software will use existing embedded Smartphone sensors to discover building features (such as hallways, elevators, exits, and stairwells) and their connectivity as a user walks through a building while carrying a Smartphone running the mapping application. Additional building signature information is collected as part of the map. The user's location, which is simultaneously being tracked using the same sensors, is used to identify the location of the discovered building features. The map accuracy and completeness will increase as the number of users increase. This indoor map database will be used for improved indoor location and routing.<br/><br/>The broader/commercial impact of the mapping software is that it will enable map coverage to increase beyond high use environments such as malls, airports, and museums. The dynamic map-building system enables maps to be easily extended to include all commercial buildings and to help address the challenge of maintaining and updating indoor map navigation data as they change over time. The data produced by the system will complement and integrate with indoor map data being made available by leading indoor map suppliers. Indoor maps can be used to power a wide array of applications, and they are clearly essential for making location-based applications work. These applications include consumer applications as well as critical safety applications. Locating people (including children) in emergency situations becomes possible if the software can both calculate their location and show it on a clear map that includes essential floor plan data that makes it easy to reach them. Navigating out of a building in an emergency is possible if the open pathways, stairwells, entrances, and exits are clearly marked on a map.