An input device for providing multi-dimensional spatial input data to a computer is disclosed. The device incorporates multiple independently operable locating members or input mechanisms, such as a roller ball for entry of two translational coordinates, a thumb wheel for entry of a third translational coordinate, and a trackball for entry of three rotational coordinates. The input mechanisms are also available for performing additional or alternative functions. The input mechanisms may be configured in several arrangements, while a single unified interface is presented to the host computer regardless of the configuration. In an additional embodiment, a seventh degree of freedom can be provided by sensing rotation of the housing containing the locating members.