Method for identifying geometric deviations of a real motion guide (213a, 213b, 215a, 215b) from an ideal motion guide in a coordinate-measuring machine having a sensor for measuring a workpiece, or in a machine tool having a tool for processing a workpiece, wherein the coordinate-measuring machine or the machine tool has a movable part (212, 214) which is guided along the motion guide (213a, 213b, 215a, 215b) and by the motion guide (213a, 213b, 215a, 215b), wherein • the movable part (212, 214) is moved in a forwards direction along the motion guide (213a, 213b, 215a, 215b), and in each case one measurement value of the geometric deviation is recorded at a plurality of first positions of the movable part (212, 214) with respect to the motion guide (213a, 213b, 215a, 215b), with the result that a first group of measurement values is recorded, • the movable part (212, 214) is moved in a backwards direction, which runs counter to the forwards direction, along the motion guide (213a, 213b, 215a, 215b), and in each case one measurement value of the geometric deviation is recorded at a plurality of second positions of the movable part (212, 214) with respect to the motion guide (213a, 213b, 215a, 215b), with the result that a second group of measurement values is recorded, • during the recording of the first group of measurement values, no measurement value is recorded at at least one first intermediate position which is situated between two of the first positions at one of the second positions, and/or wherein during the recording of the second group of measurement values, no measurement value is recorded at at least one second intermediate position which is situated between two of the second positions at one of the first positions, • for each of the first positions and for each of the second positions, an average of the geometric deviation of the motion guide (213a, 213b, 215a, 215b) is calculated from the profile of the first group of measurement values along the motion guide (213a, 213b, 215a, 215b) and from the profile of the second group of measurement values along the motion guide (213a, 213b, 215a, 215b), and in this way a group of averages is formed which are the averages of the geometric deviations when moving the movable part (212, 214) in the forwards direction and in the backwards direction. • the movable part (212, 214) is moved in a forwards direction along the motion guide (213a, 213b, 215a, 215b), and in each case one measurement value of the geometric deviation is recorded at a plurality of first positions of the movable part (212, 214) with respect to the motion guide (213a, 213b, 215a, 215b), with the result that a first group of measurement values is recorded, • the movable part (212, 214) is moved in a backwards direction, which runs counter to the forwards direction, along the motion guide (213a, 213b, 215a, 215b), and in each case one measurement value of the geometric deviation is recorded at a plurality of second positions of the movable part (212, 214) with respect to the motion guide (213a, 213b, 215a, 215b), with the result that a second group of measurement values is recorded, • during the recording of the first group of measurement values, no measurement value is recorded at at least one first intermediate position which is situated between two of the first positions at one of the second positions, and/or wherein during the recording of the second group of measurement values, no measurement value is recorded at at least one second intermediate position which is situated between two of the second positions at one of the first positions, • for each of the first positions and for each of the second positions, an average of the geometric deviation of the motion guide (213a, 213b, 215a, 215b) is calculated from the profile of the first group of measurement values along the motion guide (213a, 213b, 215a, 215b) and from the profile of the second group of measurement values along the motion guide (213a, 213b, 215a, 215b), and in this way a group of averages is formed which are the averages of the geometric deviations when moving the movable part (212, 214) in the forwards direction and in the backwards direction.