Fig. 9
From: Leak detection in water distribution networks: an introductory overview
Distribution of technologies amidst the selected models over the past four decades. The x-axis represents the decades under study. Each bar represents the papers for that specific decade and has a value of 100%. The on-site investigation is in dark grey, tracer gas is in brown, flow rate measurement is dark blue, vibration measurement is in green, GPR is in light blue, IR is in yellow, fiber optic is in grey, acoustic is in orange, and pressure measurement is in blue. The values inside the boxes represent the percentage that each capability contributes to the overall number of models per decade