With developments in the Global Positioning System (GPS) positions accurate to within tens of meters can be determined. This is combined with the ability to show radar images on computer monitors, resulting in the display of charts and radar images on one screen, all co-located by means of the very accurate navigational system. This is the basic concept of ECDIS.
Similar ECDIS-type equipment can be configured for use on fishing vessels even though they are not required to carry type approved ECDIS models. Such equipment can record fishing information as well as official charts.