The term “geofencing” is used from around 2000. It appeared in research literature by Munson and Gupta in 2002. Geofencing is one of core technologies today for location-based services (LBS) including advertising, tracking, and risk management. Szczytowski proposed an approach based on combining geofencing with social networking systems (SNS) to organize unstructured information collected from SNS. Yelne and Kapade designed a help-me application running on an android operating system based on geofencing. Detection accuracy and power consumption are very important for geofencing applications. Nakagawa et al. proposed a method for position detection whose activation frequency is determined by speed toward the target spot. Alsaqer et al. investigated accuracy and battery-use of Esri’s geo-trigger service in small, outdoor, geo-fenced areas.