Inland Water Chart Series J, Heinola-Lahti-Jyväskylä (2025)

Coastal nautical chart sets at a scale of 1:50,000 are designed primarily for boating use. Inland nautical chart sets at scales of 1:10,000 – 1:40,000 are intended for all water users.

The coordinate system of Finnish nautical charts, EUREF-FIN, is based on the WGS 84 coordinate system, which is an international maritime standard and is also used in the GPS satellite system. EUREF-FIN coincides with the WGS 84 coordinate system with an accuracy of approximately one meter, so in practical navigation the difference in coordinate systems does not need to be taken into account. All coordinates in the list of landmarks are presented only in this system.

There are still a few map products produced before 2003 in Finnish inland waters, which are based on the national cartographic coordinate system (KKJ). The reference ellipsoid is the international reference ellipsoid INT 1924 (Hayford 1910). The WGS 84 coordinate system used by the Global Positioning System (GPS) satellite positioning equipment differs from the KKJ system. These maps are identified by their green color. New maps are blue. On old green maps, the symbols of the lights are shown with Finnish and Swedish abbreviations.