Irish Vice Counties : the creation of a specific dataset on OpenStreetMap

I've been meaning to write about OpenStreetMap Ireland's townland mapping project for some time.

It's a wonderful example of how historical maps are of significant value in creating really useful data on OpenStreetMap which is just as relevant as it today as was in the past.

The immediate reason for writing about them is that I have been creating vice county boundaries for Ireland. In doing so I have not just been using the data, but the fantastic range of resources made available through the activities of the townlands project.

The Vice Counties of Ireland
My first complete draft of the boundaries on OpenStreetMap

City Stripping : building historical road layouts from todays data

Street map of Buenos Aires 1895 (plano de Basch)
Source: Wikimedia Commons

For at least one year I have been thinking about the best way to create vector streetmaps for different historical periods for the same city. The basic principle is simple: take the existing street layout and remove what is new! Essentially, this presumes that any current vector data will be more precise than digitising vectors from old maps.

I have even given the process a name: "City Stripping", but in practice my attempts so far have been less successful than I hoped. I think that  I kept too much existing OpenStreetMap data in my first attempts, because in practice I found it easier to re-trace the old data (as here for Tartu/Dorpat).