Friday 18 October 2013

Land Registry INSPIRE polygons

The UK Land Registry has released some open data as part of the INSPIRE directive. I say open data, but not very open, indeed hardly even ajar.

The Land Registry has released various data sets as recorded in this blog post, but there is a serious issue with some of their data, the polygons that show the cadastre, or property bounds, data. As you might expect, the Land Registry use the UK's national mapping agency, Ordnance Survey, to base any mapping on. So when they reproduce any GIS-based data, it is based on OS maps and, as usual, OS claims that their viral licensing clause applies. So even though the Land Registry maintain the cadastre data and want to publish it under the liberal Open Government licence,  OS prevent that by adding a personal-only, no publishing clause. This is a further example of how OS viral licensing is harming innovation and thus damaging business and potential open data users.

I have been using the Land Registry polygons to research the accuracy of creating Openstreetmap cadastre data simply by using surveys, permitted aerial imagery and local knowledge. I have decided to publish an example of what I have found under fair dealing of OS copyright and database rights. If OS are not happy about this I'm sure they will contact me and we could discuss it.

Some time ago I added all of the buildings in the postcode area HU14, Melton, North Ferriby and Swanland and added their address. In North Ferriby I also added all of the hedges, fences etc around properties. It took a lot of doing, using aerial imagery and some local knowledge. Having done it I decided that I wouldn't do any more places like that - I would only add buildings and address at most.

Now I have the means to check how good a job I managed to do, by comparing my boundary lines with the cadastre polygons from the Land Registry. I extracted a small area from their data, reprojected it to Mercator and used TileMill to render a simple view of part of North Ferriby with the cadastre polygons laid over it. Here are the three images:
OpenStreetMap data showing gardens and buildings

Land Registry cadastre polygons

OpenStreetmap data overlaid with Land Registry cadastre polygons

I am very pleased with the way the two datasets coincide. The biggest area of error in creating the Openstreetmap boundaries is the alignment of the aerial imagery - that seems to be very good in this instance. I did use multiple GPS traces to create an average trace and aligned the imagery to that. That seems to work well.

The Openstreetmap images © Chris Hill, CC-BY SA 2.0 which is based on Openstreetmap data © Openstreetmap contributors ODbL 1.0

The Land Registry data require the following statements:
This information is subject to Crown copyright and is reproduced with the permission of Land Registry

© Crown copyright and database rights [2013] Ordnance Survey 100026316

Thursday 3 October 2013

Tram depot and Boothferry Park

Recently, sladen added some tram lines close to Wheeler Street off Anlaby Road in Hull. I was surprised to see railway=tram appearing in Hull as I hadn't heard the city was joining the enlightened ones adding smart new public transport options for the commuters. It turns out that that was the site of the old tram network depot. Trams were progressively phased out by mid 1940's in favour of trolleybuses, using the same overhead infrastructure but without the rails. They ran until 1964. After a short conversation on IRC with sladen I set out to see if I could find any signs of track at the site and any other clues about the depot.

I arrived at the Wheeler Street depot tram entrance on Anlaby Road. The tracks were clearly visible in the old cobblestone roadway. It is now a private yard of some kind. I walked a little way down the roadway before being stopped by a large chap who wanted to know what I wanted. I explained about it having been a tram depot and asked if I could see the rest of the tram lines, he said no, and told me to f*** off where I'd come from. I left.

I suppose the camera round my neck and the GPS in my hand might have been intimidating, but I was polite. It is quite unusual in my experience to get a response like that when out mapping - it just made me wonder just what was going on on the site.

I tried to see into the yard from Wheeler Street but the site has buildings and high walls around it, so I couldn't see any more details.
Overall I could only confirm what sladen had seen elsewhere already, there are a few tram lines left, but not the extent of them. Judging by recent aerial images the building had gone. Older aerial images showed the shell of a building with no roof on it. I'm not able to add to that at all.

I checked the restored oneway section of Wheeler street near Wheeler primary school, confirmed that the opposite cycleway has been restored after being removed during some building work. I then moved along Anlaby road to where Boothferry Park, the football ground of Hull City, used to be. It is in the process of being turning into a housing estate. The first houses are occupied now but there is still a lot more to build. The main drag is called Legends Way with the first side road to the east called Boothferry Park Halt. Boothferry Park was unusual because it had its own railway station, only used for match days and only used until the mid 1980's. I'll need to check the site some more in a few months to catch up with the new developments.