Open Plaques

The Open Plaques project, currently in alpha, is aiming to catalogue, photograph and georeference the numerous “blue plaques” scattered around London and elsewhere in the UK. Blue plaques generally mark the house where someone famous lived, or some other event happened. The London ones are generally blue and circular, and are put up by English Heritage or the local borough councils. Other towns and cities have their own schemes.

Contributing to the project is as easy as uploading a (georeferenced) photograph to the Open Plaques Flickr group. In due course, a “machine tag” will appear on your photo, linking it to a blue plaque in the Open Plaques database, and the photo itself should also appear on the site, as long as you’ve specified a licence that allows this to be done. If the plaque is missing from the database altogether, then a new entry presumably gets set up.

Note that the iPhones automatically georeference photos as you take them, however the GPS positional accuracy is very poor unless you give time to settle enough satellites, so I manually re-georeferenced the photo in Flickr using the interactive map tool there.

The good news is that the data on Open Plaques is public domain, so can be used for any purpose. Potentially this could include adding the plaques into OpenStreetMap in the future.

Open Plaques derived the London list from the English Heritage website, which has details and addresses, but no maps or photos. This is very similar to something I did for part of my MSc dissertation last summer, which was looking at using modern GIS and geospatial techniques for enhancing Street-O maps.

Street-O events generally involve finding places and noting down a specific answer at the place, to prove you’ve been there. Blue plaques are popular with course planners, as they are generally unique, in one clearly defined location and contain unambiguous information that the competitor is unlikely to already know.

For part of my dissertation, I screen-scraped the English Heritage website, ran the addresses through Google Local to geocode them, and then plotted the results in a GIS – the idea being the race planner could then use these to build up a race map and question sheet, without having to trawl the streets trying to find plaques manually. Around 80% of the plaques were successfully placed on the map in this way, although the geocoding accuracy wasn’t always great, due to the natural inaccuracy and non-systematic placement of street addresses.

I wrote:

(5.4.2) It was decided to look at these features as one example of using a spatial dataset unrelated to orienteering to enhance the process of creating a Street‐O map for an event…

Unfortunately the blue plaque data isn’t freely available in a spatial format – users can search by postal district, but then are presented with a list of addresses rather than a map.

The pictures below show the results for the Islington area, on the left from the dissertation, and on the right the equivalent map currently on OpenPlaques. (It would be straightforward to pull the data into a GPS, from the CSV files the site provided, for a proper side-by-side comparison. I’m just being lazy by screen-grabbing the map as-is.)

Plenty more to be added to Open Plaques. The best way, of course, is to visit them – the locations can’t be copied across from my derived list, unfortunately, as the Google-derived locations are not free of copyright.

Potentially the Open Plaques database, once complete for London, will simplify this process even more, by allowing a one-step import of plaques, inscriptions and most imporantly accurate locations, into the GIS, for easy map creation.