• Post category:Articles
  • Post published:31.1.2023

Old maps for geospatial data and use

Finland’s maps are national treasures, and preserving them for future generations and ensuring their availability are important tasks. Various archives contain volumes of maps, and finding a specific map is a challenge.


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The majority of Finland’s old maps are available in the archives of the National Archives of Finland, the National Library of Finland and the NLS. Maps are also available in the National Archives of Sweden, the National Library of Sweden, the archives of the National Land Survey of Sweden, and many other libraries in Europe.

In the spring of 2020, the NLS investigated the current location of old maps, resulting in lists of maps, listing some 79,000 maps with the oldest dating back to the 17th century. Using the lists, you can search for maps by map name, mapmaker and mapmaking date.

Challenges during the investigation

The lists of maps include links to digitised maps. However, it was already identified when preparing the lists that the links are not often permanent. The National Archives of Finland had discontinued the use of one of its search systems, and links to the system stopped working. Now the links work again, and permanent links were added to some maps. However, not all maps include links.

Incomplete metadata presents another challenge. Old maps of the National Library of Finland include a title, but it can often be incomplete or even incorrect. Similarly, old maps of the NLS often include incomplete metadata.

It would be particularly interesting to identify the year in which an old map was made. Metadata may include the information, but it may be incorrect. A map may or may not have been made this year. Timing is not always easy, especially regarding maps dating back to the 16th and 17th centuries, because maps may have been printed for hundreds of years using a single printing plate, possibly with very minor changes.

Compare old maps with current maps 

Old maps can be georeferenced, i.e. converted into the coordinate systems of current maps. This is relatively easy if a map follows the map sheet division and its projection is known. A single map can also be converted into another coordinate system by identifying a sufficient number of unambiguous points on the map and their corresponding points on a modern map. There are various good examples of the georeferencing of old maps globally and also in Finland.

In the spring, Mikko Kutilainen from Shingle Oy opened the vanhatkartat.fi website, which contains all of Finland’s basic maps until 1993. The maps can be compared with modern background maps of the NLS. Kutilainen downloaded the maps from the NLS download service for old maps. As the maps had not been georeferenced, Kutilainen georeferenced some 10,000 maps.

Old maps in map image services

Currently, there are only a few image services for old maps in Finland. Municipal map image services include individual maps and aerial photos, but no comprehensive services exist besides the vanhatkartat.fi website.

The root cause for this may be that old maps have not yet been systematically georeferenced. In addition to the maps available on the vanhatkartat.fi website, the NLS has some 10,000 maps that follow the map sheet division and can be georeferenced. They could then be offered to users through an API service. As a result, maps of the areas of municipalities and the central government could be presented in time series to illustrate any changes.

National map services across the world

The map service of the National Library of Scotland (maps.nls.uk) is possibly the best example of a national map service that presents old maps. In the service, interesting maps can be searched for based on place names or map series or directly by the name of the map required. The service also features index maps and georeferenced maps.

The portal for old maps in Switzerland (kartenportal.ch) is another good example. Maps of Swiss libraries are available in the service, also including Finnish maps. The map portal of the Cartography Division of the Swiss Federal Office of Topography (maps.geo.admin.ch) features old topographic maps that can be compared and viewed on a timeline.

The best results achieved through cooperation

Converting old maps into georeferenced geospatial data requires some effort, but it is possible, as shown by the examples of Scotland and Switzerland. The best results can be achieved in cooperation between map archives, National Land Surveys and private service providers. Georeferenced old maps are not sufficient on their own, as a portal in which the maps can be presented, a search system (e.g. Finna), map metadata, and map service APIs are also required.

As a result, each of us can easily use old maps. Would it not be great if you could check changes in a specific location on a timeline, ranging all the way from the 17th century to this very day?

How to georeference maps

Bonus: Register in the MapWarper service. You can upload your own map to the service and georeference it without any separate geospatial data software. The service includes satellite images of OpenStreetMap and MapBox, but you can also use other maps, including background maps, orthophotos and basic maps of the NLS in the KAPSI service. You can download a georeferenced map in GeoTIFF, PNG or KML/WMS/Tiles format.

Historical map series added easily to map image services

  1. Digital basic maps from 2018 onwards, 1:25,000, and annual raster maps from the last seven years
  2. Printed basic maps from 1946–2018, 1:20,000 and 1:25,000
  3. Downscaled basic maps, and topographic maps, 1:50,000, from 1964–2018, and digital versions after 2018
  4. Topographic maps, 1:100,000, from 1955–1989, 1928–1951
  5. Sweden–Finland map of Lapland from 1944, 1:100,000
  6. Older topographic maps, 1:20,000 (1918–1947) and 1:50,000 (1919–1937)
  7. Maps in the Senate Atlas and printed Russian topographic maps, 1:21,000 and 1:42,000 (partly 1:84,000) from 1870–1917
  8. Kalmberg Atlas, 1:100,000, 1855
  9. General map, 1:400,000 (1873–1963, 1955–1966, 1984–1987) and 1:500,000 (1996–2000)
  10. Economic map of Finland, 1:100,000 (1912–1955)
  11. Swedish parish maps, 1:20,000 (1927–1950)
  12. Road maps, 1:200,000 and 1:400,000 (1932–1992)

Antti Jakobsson works as a chief engineer at the National Land Survey of Finland. He is particularly interested in old maps, for which he created comprehensive lists in the spring of 2020. Email: firstname.lastname@nls.fi