Location-Based Services

Location-based services (LBS) are information services dependent on the geographic location of users to deliver spatially adaptive content such as maps, routing instructions, and friend finding. Common applications include emergency response, personal navigation assistance, fleet management, and recreation. Typically, users are mobile and are located through the presence of location-aware devices, often wireless cell phones. These devices obtain positional estimates for individuals and distribute this information to a broader network through established communication protocols. If positional estimates are sampled with frequent regularity, movement traces are created, identifying all locations visited by individuals in space and time.

The development of LBS to this point has coincided with advances in geographic information technologies coupled with the proliferation of wireless communications. These efforts have been stimulated largely by the Federal Communications Commission's enhanced 911 (E911) mandate. E911 requires wireless cellular carriers to develop capabilities to position users according to predefined accuracy standards as a means of improving the delivery of emergency services. LBS development represents largely an attempt to leverage the required investment in positioning technologies to achieve commercial gain. Positioning efforts have focused primarily on satellite and terrestrial solutions. Satellite positioning occurs by embedding a Global Positioning System (GPS) client within a mobile device. Terrestrial solutions use radio location algorithms within the wireless network. Additional efforts, especially those initiated by the Open GIS Consortium, have focused on easing LBS development by creating standards for distributing and sharing locational resources across multiple entities.

Considerable attention has been given to using LBS as a mechanism for collecting disaggregate activity– travel data from users, with the possibility for data collection efforts unprecedented in both volume and detail. In cases with frequent sampling, an individual's movement trace can be measured as a sequential set of timestamped locations (x, y, t). The absence of reliable data sources has been a continual impediment to the advancement of methods and theories for understanding human geographic processes. Furthermore, rich frameworks such as Torsten Hägerstrand's time geography traditionally have also been limited by data scarcity. Analyses of observed movement traces may provide insights into spatiotemporal patterns of human interaction and their relation to broader spatial structures.

Despite potential societal benefits, LBS often are criticized for potential losses in personal locational[Page 288] privacy. Locational privacy suggests that individuals have the right to control the observation, storage, and sharing of their movement traces to limit personal identification or inference into sensitive activities and behaviors. The implementation of LBS suggests near-continuous tracking situations in which individuals have less control over what is known of their whereabouts in the past, present, and future. Nonetheless, it is difficult to dismiss the benefits of LBS even in the face of these concerns. An ongoing challenge involves identifying privacy protection strategies that maintain the utility of these services.