1. A method of measuring an object using a surface sensing device mounted on a coordinate positioning apparatus, the method comprising: (a) measuring a single surface point of a feature of the object with the surface sensing device; (b) moving the surface sensing device along a path around the feature at a fast speed, thereby taking measurements along the path, including at the surface point; (c) determining the difference between the measurement of the surface point in step a) and in step b); and (d) using the difference determined in step c) to apply a correction to the object or subsequent objects having the same feature.