The Yeoman Plotter was a plotter used on ships and boats to transfer GPS coordinates or RADAR echo locations onto a paper navigation chart and to read coordinates from the chart. It was manufactured from 1985 to 2014/2015 and was an intermediary step between traditional paper chart navigation and full electronic chart displays. It was easy to understand for people that were accustomed to paper charts and much cheaper than electronic chart displays available at the time. The continuing fall in prices of electronic chart displays, their increase in functionality such as radar overlay and the advent of cheap tablets eventually made the Yeoman plotter uncompetitive. Construction The plotter consists of a plotting surface impregnated with fine wires and a moveable "mouse" containing a sensing ring. The mouse's location on the surface can be electronically sensed. To use the plotter, a conventional paper chart is first fixed in position on the surface (the method of fixing varies between the different models of plotter; see below). It is then "registered" - the mouse is placed over three known points on the chart and a button pressed at each. Knowing the location on the surface of these points, the system can interpolate the mouse's position anywhere on the chart. In the 1990s charts in some countries had plotter reference points printed on them, and the coordinates of these points were pre-programmed in the Yeoman unit. Other charts needed the input of the reference points to be manually added. Although the device can provide some useful data on its own (positions of charted objects, distances and bearings between points), in practice it is invariably linked to a source of position data such as GPS. This enables many useful features, the most important of which is the fixing on the chart of the vessel's current position. In position mode, four illuminated arrows around a transparent area on the mouse are used. The device is pushed across the chart, following the arrows, until all four of them are extinguished. This indicates that the mouse is directly over the vessel's current position on the chart; if required, a pencil can be poked through a small hole to mark the fix on the chart. After a couple of goes, this procedure becomes instinctive and very fast. The mouse can also be used to obtain the range and bearing from the vessel's current position to any other object,