# Positioning Methods and the Use of Location and Activity Data in Forests
## 5 A Hierarchical Model for Processing and Sharing Data
With higher bandwidths, these radios support a larger number of users transmitting small bits of data (e.g., user locations) at faster transmission rates, but the cost of individual units is generally five to ten times greater than the miniaturized radios. At the top of the hierarchical data topology is two-way satellite communication. While satellite data transfer has the advantage of global coverage, and single user devices can function independently of others (e.g., without the need for mesh networking), it is also the most expensive option for transmitting data. Monthly subscription or per-usage fees compound quickly for multiple users; whereas data transfer through radio frequency is typically free in the United States after the purchase of a radio frequency license. Also, low data transfer frequencies (e.g., one user location every two minutes) make satellite-based solutions less desirable for occupational safety and health applications where real-time, local data sharing with co-workers in remote areas is more critical (e.g., [PERSON] et al. [21], [PERSON] et al. [23]) or where detection of precise equipment movements or equipment-worker interactions are required [22; 86; 87]. Figure 16 illustrates an example of the hierarchy in a wildland fire application. In this scenario, miniaturized radios share the locations of resources (fireighters, engines, etc.) during initial attack operations on a large wildland fire at moderate transmission intervals among many users. These devices also deliver summaries of fire weather data detected by a Kestrel or similar device, transmitted to a single user's smartphone via Bluetooth, and then broadcasted to other firefighters in the mesh network. In the Figure 16 example, summary data quantifying movements or activities of groups of individuals, equipment, or localized weather conditions locally are then transmitted to a higher supervisory level or between multiple teams separated spatially on the landscape using a single, higher bandwidth digital radio. For example, if four 20-person hand crews and two 3-person engine crews are working on a fire, 86 paired smartphones might be accumulating and processing data from wearable sensors worn by all individuals. Individual-level summaries of worker health and work progress based on activity recognition modeling on wearable devices could be transmitted via 86 miniaturized radios to the six supervisors (four crew bosses and two engine bosses), each of whom have dedicated digital data radios with higher bandwidth capability. Crew-level summaries of these health, work progress, and local fire weather metrics could then be transmitted via the high-bandwidth data radios to other mid-level supervisors such as task force leaders, division supervisors, or others at higher levels. Satellite data transfer may be the preferred method for Incident Command (IC) exchanges, or possibly for lower level workers to communicate reliably with a regional or national command center in situations where a local radio network is not supported. It is also the primary option for communicating single locations to a distant (e.g., urban) public safety center in the event of medical emergencies or search and rescue (SAR). Thus, raw sensor data from smartwatches and smartphones can be processed locally by those devices using coded models that summarize work activities in meaningful ways and reduce data storage and transfer size accordingly. The most critical data can then be transferred via data radios or other networks to devices that consolidate and summarize more complex spatial or temporal interactions among multiple users. In this way, the distributed system provides not only data transfer off-the-grid, but also calculations and computing power that are hierarchical, with the most critical summaries available for higher level managers. Additionally, depending on the type and urgency of transmitted data, there may be different processing and bandwidth needs for upstream vs. downstream data exchange.