According to Wikipedia: “georeferencing is a means of associating a digital image file with locations in physical space”. This is done by choosing locations on old maps which match current ones. Georeferencing results in georeferenced maps: historical maps that can overlay modern maps. For example: below is depicted Nicolaes Visschers’ map of Africa (1680) on top of the current topography.

Why do we need georeferenced maps? Three important reasons are as follows. Firstly, georeferenced maps can be displayed through web viewers, which greatly increases their accessibility (e.g. Secondly, georeferenced maps can be downloaded and opened as layers in GIS-software, which increases their applicatibility, and thirdly, the degree and distribution of the errors helps enhance our knowledge of the old maps’ geometric accuracy.

In line with a number of other major cartographic collections in both the Netherlands and abroad, the VU Library initiated a crowd-sourcing project to georeference maps from its own collection. The KLOKAN web application Georeferencer makes georeferencing easy and enjoyable! Find out how you can get started immediately by pushing the button below.

How does it work?

If you prefer getting started using instructions, we invite you to take a look at our instruction page . Here you can find a step-by-step guideline and instruction videos.

Current project

In our georeferencing project we distinguished four sets of maps based on their age: (1) 1600-1800, (2) 1800-1840, (3) 1840-1880 and (4) 1880 – 1920. More information on the current project can be found on the project page. It provides some background information and statistics, such as the progress (how many maps completed and how many left to do) and the most productive georeferencers (it can be you)!

Below are listed some of the latest georeferenced maps in the current project:

Further reading

Egmond, Marco van. “The Dutch Landscape of Online Institutional Georeferencing.” E-Perimetron 14, no. 3 (2019): 14. (available on

Hackeloeer, Andreas, Klaas Klasing, Jukka M. Krisp, and Liqiu Meng. “Georeferencing: A Review of Methods and Applications.” Annals of GIS 20, no. 1 (January 2, 2014): 61–69.

Storms, Martijn. “Maps in the Crowd: Results of a Map Georeferencing Crowdsourcing Pilotproject.” E-Perimetron 12, no. 3 (2017): 109–18. (available on