Abstract: A proximity detecting system for use with an agricultural equipment or implement such as a crop sprayer, for determining the position of the implement, e.g. the end of a spraying boom relative to the edge of the previously cultivated or sprayed area. The system has an electronic imaging device, e.g. a CCD array, mounted at the end of the implement or sprayer, which shows the location of a marker placed at the edge of a previously cultivated or processed swath. The position of the marker is shown on a visual display located in the operator's cab. A deviation of the marker from a predetermined position on the display alerts the operator of an overlap with, or miss, of the boundary of the previously processed swath.