A localization denotes the position (space and time) and the strength of a suspected fluorophore emission. A localization denotes only a suspected position because the high noise conditions in photoswitching micrsocopy introduce false localizations, either through background noise or multiple close-by emitters.

Localization coordinates are not given on a lattice as pixels are, but are rather subpixel-accurate. The accuracy is mostly given by the emission strength and the background noise as described by [Thompson2002].