Old Maps Online contains a collection of over 400,000 maps from all over the world from various participating institutions dating from 1550 to the present, which it is hoped can be digitised. The digitised collection is free and available to the public to view and analyse in a variety of ways.
Match a location on an old map contained in the map collection to one on a modern map. Once you have identified three or more points, you can superimpose the old map on the new one, and clip it to fit. This makes it easier to visualise the old map and creates the ability to search old maps. There is a one minute video to explain what to do, as well as written instructions.
No cartography experience required to participate in this action.