Saturday, 30 April 2011

Round the hill



A month ago the ITO OSM analysis was showing my local area as having reached 74% coverage. It ranked about half way up the list, with roughly equal numbers of other areas showing better and worse levels of coverage.

Checking out some of the inconsistencies has given me plenty of excuses for pleasant outings over the last month. Several bank holidays later we have just passed 90% coverage, and risen to rank three-quarters of the way up the table. About a quarter of local areas still have better coverage, and of course, several of them are also improving, so the bar is continually rising.

That still leaves a gap of 10% to close, and some of the remaining inconsistencies are a bit of a puzzle. This is one. With that sign, the OSM name tag on the road was previously set as "Knowl Hill Common (Round the Hill)". I'm not sure, but I think it might have been my contribution in the first place. It certainly seems a reasonable interpretation to me.

However, on OS Streetview this road is named "Knowl Hill Common". A cursory search of the internet suggests that local addresses also tend to prefer "Knowl Hill Common". On the ITO analysis, half of the road was highlighted as inconsistent, and the other half wasn't.

After mulling this over (note to self: must get a life), I decided to change the name tag on OSM to "Knowl Hill Common", with an alt_name tag of "Round the Hill".

Of course the beauty of all this is that anyone who feels strongly, or has better local knowledge. can always change it back, or change it to something different. The location is here.

At the same time, and again thanks to ITO, I've uncovered a couple more named roads that I'd previously missed, despite having ridden past them regularly for the last three years. I can't believe there are so many of these bits and pieces that I hadn't noticed before, but in my defence, both of these look a bit like private driveways from the road. Closer scrutiny on the ground shows that they do have real names, and both are now fixed.

And finally, to my relief, I've managed to fix a mess that I made of one of islands in the Thames. I screwed up one of the riverbank multi-polygons last night. I realised shortly after that this had drained a short section of the river upstream from Windsor. It wasn't a difficult mistake to fix, but it was a bit of an uncomfortable wait before the solution was rendered again. All seems to be well now.

Onward and upward.

Somebody tried to steal my old bike last week

We only have room in the shed for one bike, and the space is taken by the touring bike that I got last year. My older hybrid used to live in the shed, but now it hangs on a rack round the side of the house. It's outside, but protected from the worst of the weather, and secured by a padlock and wire cable.

On Friday morning we discovered that overnight somebody had removed the cover, and lifted the bike off the rack. However, they must have been deterred by the lock, and the bike was still there, lying on the ground.

The bike wasn't visible from the street, and we are tucked away on a side road, out of the way of passing traffic. So it's a mystery what anyone was doing at the back of the house in the first place. Presumably they had come over the garden fence looking for a short-cut, seen the bike, and thought "I'll have that", before realising it was going to be more trouble than it was worth.

We keep the second bike for visitors, and I use it occasionally - such as when my main bike was in the shop for repairs. Most of the time it just hangs there gathering cobwebs. That seems a shame, so rather than just putting it straight back, I've cleaned it up today, checked it over, pumped up the tyres and taken it for a ride. It's the first time it's been out in months. After more than a year using a new bike the differences in the ride were obvious straight away, but it made a change, and I soon adapted. I'm probably kidding myself, but when I clean a bike I can usually convince myself that it is running particularly nicely.

I went a few miles out to Knowl Hill, looking for a few things that I knew need fixing on the OSM map, but more of that shortly. In the meantime I might not have made best use of both bikes over the last year, but I'm glad that I still have the option.

Friday, 29 April 2011

Wedding present

The spectacle has been impressive, but the coverage is becoming too much to bear.

Nevertheless, who could do anything other than wish the couple well? So I spent a bit of this morning creating a wedding present for them.

This maps the loyalty of the nation, according to the proportion of street names with royal connections. On the chart, yellow presents a high proportion of royal street names, and red represents a low proportion.


The most popular examples of street names with royal connections include Victoria Road, King Street, Queen Street, and various other combinations of Victoria (...Street, ...Park, ...Avenue). Princess Road and Princess Street come next, ranking seventh and eighth by total length. Together these eight names account for about half of street names with royal connections. King Edward Road ranks ninth, Queen Elizabeth Way ranks tenth, and Prince of Wales Road ranks eleventh by total length.

Altogether royal street names account for about 0.05% of the total.
The highest proportions are in the City of London and Denbighshire. The lowest proportions are in Harrow and Peterborough.

The street name data came from the OSM database, and the boundaries from Ordnance Survey. Postgresql, Postgis, Open Office and Quantum GIS did the heavy lifting.

Monday, 25 April 2011

Sustrans FAQ

Sustrans are great, but their online mapping isn't, and this FAQ response doesn't make sense to me....

Why don't Sustrans use Google Maps or OpenStreetMap?

A Google or OpenStreetMap API (a map that can sit within another web page) re-loads the data attached to it each time you move or zoom the map. Our dataset is over 80Mb so this would run very slowly.

We use Ordnance Survey 1:10 000 and 1:25 000 scale maps as our backgrounds for several reasons:

They are based on the same map product and so will match up with each other at each zoom level. This means that routes will appear correctly against the different backgrounds. For example, a route plotted down one side of a carriageway against the 1:25 000 will appear on the same side of the carriageway when viewed against the 1:10 000 background.

Google mapping is not consistently detailed enough in all areas of the country for our needs. Also areas of shadow created, for example by tree-lined lanes, can obscure important information for cyclists and walkers. We believe that Ordnance Survey backgrounds give much better detail in both rural and urban areas.

From http://www.sustrans.org.uk/about-sustrans/faqs

Sunday, 24 April 2011

Which councils chose the most boring street names?

The widest variety of different street names is to be found in central London. Manchester, Scottish cities, and some English ports also show quite a lot of variety in their choice of street names. The least interesting mix of names tends to be found in rural counties to the east of England. East and North Yorkshire, Norfolk, and Lincolnshire all have a high proportion of common names, and use little variety in naming the rest of their network.

The bottom line is that the most interesting names are in Islington, and Kensington & Chelsea. Norfolk must try harder.

Allowing a bit of slack for spelling variations and tagging errors, the OSM database holds well over 250,000 different street names across the whole of the UK network. But some are more common than others. Only 25 of the most popular street names account for almost 5% of the named network.

"Station Road" and "High Street" are the most popular names. These represent respectively just over, and just under 0.5% of the total. "Church Road", "Church Lane", "Main Street", "Mill Lane", and "London Road" are also among the 25 most conventional names. However, the pattern is not consistent. In parts of London and Scotland the most common names account for less than 1% of the network; while in other parts of the country the 25 most common names account for almost 10% of the named road network.

Outside the most common names, the bigger authorities tend to use a wider variety of names - as one would expect because they operate bigger road networks. The big counties, like Kent, Essex, Lancashire and Hampshire each uses more than 1,000 distinct street names. On the other hand island councils such as Orkney, Shetland, Western Idles, and Anglesey; and smaller authorities on the mainland use a much smaller number of different names. Adjusting for the size of each road network, central London boroughs, and some cities, such as Stoke, Manchester, Bristol, and Derby each use a wide variety of different street names in proportion to their size, while shire counties generally show less variety.

The local authorities with the highest proportion of roads using common street names are:
  • East Riding of Yorkshire
  • Norfolk
  • Moray
  • Bedford
  • Lincolnshire
The local authorities with the lowest proportion of roads using common street names are:
  • Lewisham
  • Western Isles
  • Islington
  • City of Westminster
  • Kensington and Chelsea
The local authorities with the most diverse mix of different street names are:
  • City of London
  • Tower Hamlets
  • Stoke-on-Trent
  • Islington
  • Kensington and Chelsea
The local authorities with the least diverse mix of different street names are:
  • Norfolk
  • North Yorkshire
  • Lincolnshire
  • Western Isles
  • Orkney Islands
And as exercises in unnecessary and meaningless statistics go, I reckon all that will take some beating.

Saturday, 23 April 2011

More dreadful weather for armchair mapping

The weather is glorious again today, so I set out early and took the scenic route to Windsor. I pootled around Dedworth for a while writing down some of the street names that are missing or incorrect on OSM, so I could add them when I got home. Then I rode back through Bray, with a stop at Boulter's lock where I treated myself to an ice cream and watched the boats for a while.

Dedworth is a suburb of Windsor, which happens to lie between some of my regular rides. It had quite a few missing street names, and it's a reasonable distance for a ride of a couple of hours. Those are the reasons I picked it out, not because I had a burning desire to visit Dedworth. It seems to be made up of a series of developments that mostly date from the 1930's to the 1970's. For example, here's a Pathé news clip about some self-build activity here in the 1950's.



While I was updating the OSM data I started to get curious about some of the street names, which are a bit unusual. It turns out that Dedworth has Saxon origins, and predates Windsor. Although the housing is relatively modern, they have used some names with historical associations. Examples I logged today include "Filmer Road" (Filmer was one of the Windsor Martyrs, burned at the stake for heresy in 1543), "Frymley View" (Frymley was a 16th century mayor of Windsor) and "Surly Hall Walk" (Surly Hall was a local inn, used by pupils at Eton). I also added names to some cul-de-sacs off Gallys Road, which is named after the landlord of the Garter Inn, who appears in Shakespeare's Merry Wives of Windsor.

The history of Dedworth: not as boring as I thought.

Friday, 22 April 2011

Traffic delays



I've ridden past this sign a few times.

Spotting it out of the corner of my eye, I thought it read:

Traffic delays
Likely road rage in this area
Good Friday
9am - Noon


So I stopped to take a picture, and was disappointed to realise my mistake.