A data processing apparatus is disclosed which processes data for operating a movable segment of a machine in correspondence with a position of a controller. The data processing apparatus includes a control unit or processor configured to obtain controller information including the position, when an operator operates the movable segment using the controller, obtain capture image data generated by image capturing of the movable segment while the movable segment is operated in correspondence with the position, generate composite image data by superimposing a controller image indicating the position included in the controller information, on an area corresponding to the movable segment on the capture image data, and display the composite image data on a display device viewable by the operator.