The primary goal of Ingress is to defend the takeover of the human race by an unknown “Shaper” force or, depending on your perspective, to assist in an “Enlightenment” of mankind through an alliance with the Shapers. This is accomplished by aligning with either the Resistance or the Enlightened faction and by creating “Control Fields” over geographic areas. Progress in the game is measured by the number of Mind Units controlled by each Faction (visible on the Intel Map).
XM Control Fields are established by claiming Portals and then linking Portals together to form Fields. More powerful Portals can link over longer distances (up to hundreds of kilometers). The link range of a Portal is determined by the power of the attached Resonators. Portal Keys are needed to form links.
When three Portals are linked to form a triangle, a Control Field is established over the region. It will be rendered on the Scanner as a hazy blue or green field over the area. The number of Mind Units claimed is related to the population density of the area covered. Cities yield more Mind Units than rural areas.
Your ultimate goal is to cooperate with other players in your Faction to secure or liberate the entire world.