Daily Archives: 25/02/2012

On Shifting Sands

The British Library recently called for volunteers to help ‘georeference’ over 700 historic maps of London, England and Wales.  They digitized the maps but needed the assistance of real live human beings to read the maps, and link them to equivalent maps on Google Earth, in place, size and projection.

It’s yet another fascinating experiment in crowd sourcing – but I’m afraid you can’t join in, because they got so many volunteers that the work was completed within a week!  They now plan to load another 1000 digital maps.  If you want to get involved you can register and they will notify you when they are ready to roll.

According to the accompanying video, the technology of linking past and present geographical features seems fairly straightforward: they use the Tower of London as an example, and it’s been in the same place for nearly a thousand years.

Tower of London 1597

Other geographical features on a landscape are trickier.  Where is the Fleet River these days?  Rivers are particularly vulnerable – they are constantly being diverted by urban development, or silt up because of agricultural development upstream.

Coastlines change too.  Continue reading