A distance that characterizes the ability of a logging measurement to resolve changes in the formation perpendicular to the tool. Alternatively, the term refers to the smallest distance for which a significant change can be detected. The resolution is a feature of the radial response, which is often summarized by a geometrical or pseudogeometrical factor. A measurement with good or high radial resolution will have a sharp peak in the radial differential geometric factor at some distance from the tool.