Places to map

As the weather improves we are all going to be out and about tracing roads for OSM. Larger towns and bigger areas that need attention are fairly well known, but as the amount of content on the map improves it can be difficult to find smaller and more local places where a short session could make a difference quickly.

So I've been messing around with OSM data again, trying to figure out a way to highlight areas that look as though they need some attention. The result is here.

This is very much a first cut, and it doesn't always get things right, but I think it gets them right often enough to be useful.

It starts with a list of about 1,600 UK settlements, and then uses a variety of techniques based on road density, type of road, and population to try and guess which settlements seem to have a lot of roads on the map for their size, and which don't have many. The green areas look as though they are well covered, and the red areas look as though they could do with some attention. The grey areas fall somewhere between the two.

There is more detail on how it works, and the subsequent discussion on the Talk-GB mailing list

It needs more work to improve the process, and a number of good suggestions are coming in on how to do that. I'd welcome more comments and ideas. But more important than perfecting the measurement is to get more roads on the map. So what I really hope is that this will help members of the community to find some handy places where they can quickly make a difference by plugging a few gaps.

Please remember though that this is a little bit hit-and-miss. It's probably a good idea to check some other sources as well before rushing out to your nearest red blob with the GPS.

Browsers

I'm always a bit surprised about the degree of fervour around browser preferences. I mostly use Chrome at the moment, but  I switch around a bit. Each has strengths, but for most purposes I can't see a lot of difference between them.

Apparently Internet Explorer is still the most widely used, accounting for around 60% of traffic. Firefox is second with almost 30%, then Chrome and Safari have around 5% each.  Opera, and the others make up the remaining few percent.

By contrast Firefox represents 48% of the traffic here, followed by Chrome with 24%, IE with 17% and Safari with 5%. The others make up the other 5%. My visits will be bumping up the Chrome figure a bit, but even allowing for that there's a distinct preference among Tlatet readers for the market challengers over the market leader.

It's an open question though whether that means we are more sophisticated, more free-thinking and independent, or just pig-headed.

Bracknell

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Around here the most noticeable gaps in the OSM map are in Bracknell, and today I decided I should go and try to fill some of them. My GPX trail, and the results are shown in the map above.

There has been some discussion on the Talk-GB lists about whether the locations suggested for this summer's mapping parties are going to be attractive enough, but there are also comments that in practice it doesn't make much difference. It wouldn't be difficult to be a bit sniffy about Bracknell as a mapping destination, but to my mind that misses the point. This isn't tourism. From home it's a pleasant ten mile ride out to Bracknell through the Walthams and Shurlock Row. When I got there, the residential areas that were missing weren't anything remarkable, but they seem pleasant enough. For me though, the real pleasure is in the ride. Mapping a bit of Bracknell is as good an excuse as any to get on the bike - with the added bonus that I'm not just trundling around - there is some purpose to the exercise.

As a relatively new town Bracknell is quite good at separating cycles and cars. There's a grid of fast roads, but then the residential roads are arranged so that they can't be used as rat-runs. On top of the road network  there is a network of footpaths and cycle paths so that people walking or cycling have access to plenty of short-cuts that cars cannot use. I imagine that it all works nicely for a local who knows their way around. But when you don't know the town it's a bit difficult to navigate on a bike. In practice the cycle routes seem quite fragmented and complicated, and the through roads are fast and busy. It seems to me that this should be an ideal environment for route finding with a GPS. A GPS should be able to get me from one side of Bracknell to the other, without needing any local knowledge. But there are currently lots of gaps in the map.

Today I was on the bike, but my intent was to plot roads. I didn't want to confuse the trace of the roads with paths that are restricted. So I didn't trace all the connections that were open to bikes. As a result, anyone who uses my contribution to route-find on a bike could be taken around some unnecessarily convoluted journeys. There are probably ways that I could have done this better, and I should give it some thought. In the meantime, there are a few more miles of residential road in north-west Bracknell that weren't on the map a few hours ago - but I'm conscious that I've only contributed part of the data that needs to be added.

When I did the editing, I was reminded that although I've added the odd detail to OSM from my trips over the lest few weeks, and I've edited some content from NPE, I haven't added any significant traces since before Christmas. It's a bit of a call to action, and there are still some gaps to fill in Bracknell.

Capital smooth and hard road

The A4 is a historic road in England, which runs from London to Avonmouth, near Bristol. It was the main route from London to the west of England. As here in Maidenhead it is known for much of the way as the Bath road. It did originally only run as far as Bath, but in 1935 the A36 between Bath and Avonmouth was renumbered as the western end of the A4.

The heyday of the road was in the nineteenth century as a coaching route, up until the arrival of the Great Western Railway, which reached Maidenhead from London in 1838, and linked London and Bristol from 1841.

In 1821 mail coaches were averaging 8.75 mph along here between London and Bath (including stoppages). That's about the same speed as I average over a full day on the bike (including stoppages). They left London at 8pm, and reach Bristol the following morning at 10am.

Fast passenger coaches (stage coaches) were reaching 11 mph or more, and by 1837 there were fifteen passenger coaches a day between London and Bath, as well as two mail coaches. From then on, as the railway extended out towards Reading the start point of the coach journey moved nearer to Bristol, and once the railway was complete the coach services ended.

This picture was taken just east of Maidenhead Thicket, which along with Hounslow Heath (roughly where Heathrow Airport is now) was one of the notorious spots where coaches feared an encounter with highwaymen. The highwaymen at Hounslow heath would target rich travellers going from London to Bath, while those at Maidenhead would target those travelling from Bath to London. Nevertheless, Maidenhead was a popular overnight stopping point for those travelling west who preferred to cross the thicket early in the day (presumably while the highwaymen were still having breakfast).

"The roads of England and Wales: an itinerary for cyclists, tourists, and travellers, containing an original description of the contour and surface with mileage of the main direct and principal cross roads in England and Wales, and Part of Scotland" (which is a blinder of a book title), has this to say about the road between Maidenhead and Twyford in 1898 - "hill to mount out of the town, then first rate level road to Stubbings Heath or Maidenhead Thicket, and the rest is rather hilly by Littlewick Green, Knowl Hill, Kiln Green, and Hare Hatch; capital smooth and hard road. Pretty scenery".

Since the early 1960's the A4 between Maidenhead and London has been been paralleled by the M4 Motorway, which extended as far as Swindon in the early 1970's.

And now, having shifted traffic off onto the railways, and the motorways they are going to cap it all by building a cycleway. It's all part of the local authority plan to encourage pupils to cycle and walk to school, and they hope it will also reduce congestion and parking problems. It involves some new cycle paths, and signage.

I applaud the policy of encouraging cycling. And as I regularly face the problem of crossing this part of the A4 at busy times of day I look forward to the end of March, when I can change my route slightly so that the new toucan crossing speeds me on my way.

Charles Harper - The Bath Road = http://ia341038.us.archive.org/3/items/bathroadhistoryf00harp/bathroadhistoryf00harp.pdf

The roads of England and Wales = http://www.archive.org/details/roadsofenglandwa00howa

Society for All British Road Enthusiasts = http://www.sabre-roads.org.uk/wiki/index.php?title=A4

Motorway database = http://www.cbrd.co.uk/motorway/m4/

A4 Cycleway =
http://www.rbwm.gov.uk/web/news_22609_a4_newlands_cycle_route_west_maidenhead.htm

Road densities on OSM

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This is one of those things that you do, then you are not quite sure whether it was worth it or not.

I calculated the road density for each of the "Pay scale areas" that arrived with the OSM Naptan import. I thought that these would be fairly thickly populated areas, so a low road density would highlight places where there were roads missing from the map, and hence help to prioritise more attention.

Road density is calculated as the length of roads in km, divided by the area in sq. km. I've included motorways (and links), primary, secondary, tertiary, unclassiifed and residential roads. I've not included cycleways, paths and bridleways, etc.  The data extract I used is actually a few weeks old, but that shouldn't make a lot of difference (unless someone has added a mass of new roads in a particular area).

The highest quartile of areas (by road density) are shown in blue, then the following quartiles in green, orange and red. In other words red areas don't have many roads for the area, blue areas do.

Looking at the result, things obviously are not as simple as I expected. Anyway, for what it's worth, this is what it looks like. Maybe someone else will spot a way of making use of the information.

Cycling participation

I missed this when it came out in December, but better late than never. Sport England published the results of their Active People Survey including a factsheet on Cycling, which is here. The full list of diferent sports is here.

On the basis that they surveyed (at least one 30 minutes session of at least moderate intensity per week) cycling ranks as the third most popular participation sport after swimming and football, but ahead of athletics. Cycling is more than twice as popular as golf, from which I gain some satisfaction.

It looks as though in 2009 1,880,0004 people cycled at least once a week (4.50% of the adult population), which is an increase from 4.26% a year earlier. The increase was almost entirely accounted for by men in their early 20's, and late 30's to early 60's. There was significant growth in cycling in the North East and South West of England. The proportion of cyclists engaging in competition or tuition is relatively stable, but club membership has increased.

Result of a rainy weekend

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It's been a rainy weekend, so I've not been out on the bike. Instead I've been playing around with OpenLayers, trying out an idea suggested by Richard Fairhurst that shows how scale varies when you plot a round planet on a flat screen. I've made some progress, and I think this illustrates the idea. It's all a bit clunky under the hood, though, because I'm still climbing a steep learning curve on how all this stuff works. If this weather continues I might get a chance to refine it a bit.

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I've started to make a few improvements.

For one thing, it's now possible to configure the units used (as "metric" or "imperial") and the colour (using the standard html colour set = aqua, black, blue, fuchsia, gray, green, lime, maroon, navy, olive, purple, red, silver, teal, white, and yellow, plus browser dependent alternatives). Using darkblue matches the OSM controls.

Our former colonies should note the English spelling of the "colour" parameter.