Figure 16.1 shows the strength and reach of a common Wi-Fi network on a street in

Oslo. To create photographs like this we have developed a technique using long

exposure photography and a specially designed measuring rod that visualises Wi-Fi

signal strength as a bar of glowing lights. The height of the bar corresponds to the

strength of a network in a specific location, and, when moved through space, the

measuring rod displays the changes in the Wi-Fi signal. This is captured using long

exposure photography and the narrow bar of light is stretched into a cross-section

of the network that shows how it changes through the physical environment.