Simple integrated control for zoom/pan functions

A simple, integrated control (12) for pan and zoom of a display of data represented by a very long data record is in the form of a control knob (10) having an outer ring (14) for controlling pan and an inner knob (16) for controlling a zoom factor. A zoom function is turned ON either by turning the inner knob (setting the zoom factor to a default value) or by (i) pressing an adjacent zoom (18) or pan (20) button or (ii) turning the outer ring (setting the zoom factor to a prior value when the zoom function was turned OFF). The zoom function may be turned OFF by turning the inner knob to set the zoom factor to 1X or by pressing the zoom button. The outer ring has individual positions divided into two groups: one group for controlling pan rate within a zoom window displaying a portion of the very long data record defined by a zoom box within a main window displaying the very long data record; and the other group for controlling pan rate of the zoom box within the main window for rapid movement from one end of the record to another.