The most well-known global network was discovered in the mid 20th century by Dr. Ernst Hartmann. It is described in detail in his book Krankheit als Standortproblem (The disease as a localization problem).
The Doctor deduced its existence by comparing thousands of georhythmographs. His work indicated that the electrical resistance of the human body was decomposed on a grid oriented by the cardinal points and that acquired his name.
In mid-latitudes, they are parallel lines with a distance of 2.5m East-West and 2m North-South. Between these geometric lines there is a neutral zone.
The intensity of the Hartmann lines increases during the night. Therefore, the effects on human health occur especially during the hours of sleep.
Dr. Hartmann provides evidence of effects on human health in his book. They occur especially in the points located above the vertical of a Hartmann network crossing or a single Hartmann line crossing with other geological disturbances such as groundwater or faults, usually in the form of an increase in anxiety, insmnia, trembling and cramps.
It should be noted that living beings should already be used to these networks, as they surely would have always existed. However, it seems that human activity can affect them. Geobiologists detect it more intensively in urban areas with greater artificial contamination by electromagnetic fields compared to more rural or natural environments, locations where they emit smoother radiation.