If maps are digitized and geographic coordinates provided, you can link them to other map layers. That way you can easily compare the information from different map layers.
Geoplaza is the place where you can view and use these digital geographic map files. The maps typically have OpenStreetMap as underlying map layer, but you can also use Google. Themes on Geoplaza comprise topography, soils, geomorphology, postcode areas and Dutch estates. In Geoplaza you can download and edit selections in a GIS (Geographic Information System).