X-Y Plotter

An X-Y plotter is an analog recording device that draws a curve with a pen whose horizontal deflection follows one input signal and vertical deflection another, producing a permanent paper trace. In older hydrographic and survey work it plotted echosounder depth against distance or time and drew position fixes and cross-sections, the graphic chart recorder of an analog echosounder being a depth-versus-distance variant. The permanent paper record could be checked and digitized later. Digital data logging and electronic plotting have replaced it, but the analog depth trace it produced remains the format behind many archived legacy survey records.