Abstract: A device (gage, data station, and software) and method to measure mean radius and deviations from mean radius of nominally cylindrical or conical shapes in a plane perpendicular to the nominal axis of revolution using curvature measurements at uniformly spaced intervals about the circumference is described. The system divides the contour of interest into equal segments and measures the local curvature at each point. The group of measurements combines with a closure constraint to produce a condition of mathematical overcompleteness. This is used to minimize the accumulation of measurement error.