The line shape tolerance is a shape tolerance with respect to the profile of a line. The toleranced profile must lie in each plane between two equidistant envelope lines whose distance is defined by circles. Compliance with the line shape tolerance is particularly important for edges, since lines on components often occur in the form of edges. If an edge deviates too much from its intended geometry, for example due to wear, the functionality of many designs is endangered. Depending on the measuring task, deviations can be detected using a variety of tactile and optical metrological methods, which can also be combined. A professional assessment helps to choose the right method.