A visualization of man-made magnetic field fluctuations during an Amtrak train ride (pacific surfliner route) from Oceanside to Los Angeles Union Station. It provides a qualitative look into a dataset on an invisible realm. A motion tracking program was used to quantify the needle movement of an analog trifield gaussmeter located inside a coach class car.

Needle movement reflects changing milligauss intensity of AC magnetic fields. Intensity changes take the form of bars each containing 5628 data points represented by ellipses. The greater the radiation, the wider and taller the ellipses. Warmer colors also reflect higher levels (see legend). Overlapping of ellipses and increases in color saturation reflect accumulation of passenger exposure. "Detailed view" experiments with a finer grained breakdown of the same data. "Fixed width" view minimizes the accumulation effect, providing better temporal detail. Spikes occur near intermediate station stops and little activity occurs during middle of the trip.