Metria has been commissioned by the Swedish Environmental Protection Agency to georeference historical maps so that they can be opened in a Geographical Information System (GIS) and used to identify historically interesting places such as wetlands, arable land and farms.
This is a series of historical maps covering a large part of Sweden, which until now have only been available in paper form at the National Archives and have now been digitized and thus made more accessible. The maps were drawn by hand by surveyors in the 19th and early 20th centuries - so-called Häradkartor and Stomkartor.
Metria has digitized the maps and with an automatic method removed the outer edge of the maps and georeferenced the map files.
The master maps are a historical source material that shows the location and extent of former cultivated land, land used as fields or hayfields. Although the landscape is shown in a fairly general way, wetlands are often clearly marked.
The map, adjusted according to four corner control points compared to the orthophoto. The image at the bottom shows the map on top of the orthophoto with 50% transparency. Houses in the map are about 15 m shifted to the northwest.
The aim has been that the maps can be opened in a GIS and used with as little further processing as possible. The maps can be used to identify sites of historical interest such as wetlands, farmland and farms. More than 1,500 maps have been processed, with accuracy ranging from 20 meters in the southern parts to 200 meters in the northernmost parts of the country.
The maps can be downloaded from the Swedish Environmental Protection Agency's website: Historiska kartor (naturvardsverket.se)
GIS (Geographical Information Systems) are computer-based systems used to collect, store, manage, analyze and present geographical information. With the support of GIS, it is possible to produce analyses and decision support based on large amounts of data and to visualize complex information in a simple and clear way to see patterns and trends.