Using Citizen's MapSite in Georeferencing

Finnish localities, addresses and coordinate transformations

Citizen's MapSite <http://kansalaisen.karttapaikka.fi/kartanhaku/osoitehaku.html?lang=en-GB> can be used to find Finnish localities and addresses, and to transform Finnish coordinates into decimal degrees (~WGS84). It’s maintained by National Land Survey of Finland. See also the official instructions in English.

Main features relevant to georeferencing:

Localities can be found with the search function by their name, address or coordinates. If the search gives multiple results, you can choose which ones to display on the map. Use Ctrl and Shift -keys to select multiple places to be displayed.

When searching for street addresses you must first write the street name and then the number (e.g. Teollisuuskatu 23).

When searching municipalities without more exact locality information, use the search by place name and write the name of the municipality to both the Search word and Municipality fields.

To get coordinates, first click the location so that the map is centered on that spot. Then click “Transform”-link and after that “Transform”-button. Then a new pop-up window appears which shows coordinates in different formats. The EUREF-FIN-coordinates are equivalent with WGS84- coordinates with accuracy of less than one meter (see MapSite instructions for details).

Don’t trust the coordinates below the MapSite logo, because they are sometimes in national grid and sometimes in uniform grid coordinate format. The format depends on the zoom factor used, and is not told alongside the coordinates.

To transform Finnish coordinates into decimal degrees, use first the search function to center the map on those coordinates, and then get the decimal coordinates as described above.