Examples of rescue beacons in southwest Arizona as seen on satellite image, accessed via Google Earth.

The beacons were geolocated using a variety of open-source investigation methods such as Freedom of Information Act requests and satellite imagery. Public records found online, such as trail guides, tourist blogs, or existing maps were helpful in identifying the general location of several beacons, paired with a process of intensively studying satellite imagery via Google Earth to confirm the exact coordinates.

Key visual features make it possible to identify the beacons in satellite imagery, including:

• a square cement base, which tends to appear as a cluster of brighter grey or white pixels
• proximity to a graded road, necessary for installation
• circular patterns in the sand created by “tire drags” that produce a flat area necessary for installation
• distinct shadows, which are longer, thinner, and more angular than the shadows of surrounding cacti
• the shape of 2-3 square shadows, vertically stacked (the solar power panel, the call box, and signage).

While the U.S. Border Patrol installs and maintains the beacons, the agency frequently fails to respond to Freedom of Information Act requests. Instead, FOIA requests were sent to land management agencies, such as the Fish and Wildlife Service and National Park Service within the Department of the Interior to gather information about the beacons locations within specific land boundaries. The National Park Service was able to provide a single document of beacons installed on the Organ Pipe Cactus National Monument current to the date of the request (March 2019), while the Fish and Wildlife Service provided a large number of documents including correspondence, maps, and lists of coordinates, all of which were undated, and many of which were outdated.