Space4Cycling in Crystal Palace

I’m supporting the Space4Cycling campaign in the Crystal Palace ward, where I’m standing for the Green Party.

I often cycle up and down Anerley Hill on the way to work. It’s a steep bit of road, difficult for those of us who aren’t zipping up to Cadence every weekend on expensive road bikes. Cycling uphill without wavering a little is hard work, so providing some protected space at the expense of a little car parking makes perfect sense.

Of course some people who currently park their cars there will lose out. But I want to see streets in Crystal Palace, London, the whole of the UK transformed to serve the needs of people on foot, bike and public transport, and this can only happen at the expense of cars because we have limited road space.

The alternative is to leave almost 20,000 vehicles a day trundling along Anerley Hill, creating peak hour traffic jams. This level of traffic is responsible for illegal levels of air pollution, which will remain until at least 2020 if we don’t do something drastic. Find out more about this here. If you walk down to Anerley Road on a school day, you’ll see dozens of children buying fast food, but very few on bikes. Designing roads for cars at the expense of bikes is unhealthy and bad for the environment.

I would also like to introduce 20mph limits on far more roads in the area, particularly for rat runs like Thicket Road, introduce ‘filtered permeability’ to more roads to reduce traffic, and fix the various barriers, potholes and speed humps that make cycling through Crystal Palace Park confusing and unpleasant.

I want to make it easy, safe and pleasant for everyone to cycle in Crystal Palace, whether they’re an 8 year old going to school in the morning, or a fit 80 year old heading up the hill to the shops.

Some thoughts on the Space4Cycling campaign

I think this new campaign from the LCC and all the local cycling groups is brilliant. It is showing yet again that cyclists can be mobilised to make their voices heard in the democratic system, and I only hope it has a big an impact on local councillors as their lobbying of the London Assembly has had.

I also hope that councillors elected in May honour their promises. I do wonder at the Labour councillors signing up in Southwark, a borough I used to live in and cycle through every day. The council has spent four years doing next to nothing for cyclists, while scrapping the London Cycle Network from its Transport Plan and actually removing cycle lanes from busy roads.

As the Stop the Killing campaign found, many other councils are just as bad. Are all these candidates honestly going to push for the cyclists’ proposals having failed to do so in the past four years? One can only hope.

My one other reservation is that it is difficult for smaller parties and independent candidates to get onto the site. For those who have never fought an election, I can assure you that it’s a huge challenge for small parties dependent on volunteers with full-time jobs just to get all the paperwork in to the returning officer, let alone get a list of candidates out to anyone who asks and respond to lots of lobbying requests.

This campaign web site has been live for some time now, and while very well organised parties can get their candidate lists out nice and early, many others won’t have a final list until nominations close next week.

At the moment, the web site gives a very poor impression of the Green Party, for example, even though we have consistently been the most pro-bike party in the capital. That isn’t just my biased opinion, it was also the view of the Londoners on Bikes campaign in the 2012 elections.

So at the time of writing over 12,000 people will have contacted an incomplete set of candidates, and might think the missing candidates and parties have nothing to say about cycling. I hope you, dear reader, will bear that in mind and hold off sending your lobbying email for a couple of weeks.

Analysing Southwark’s natural geography

Following my map of London’s green and blue infrastructure, I have been working on some analysis of the land uses.

I was inspired and encouraged to try this by Liliana’s interesting work called “imagining all of Southwark“. Lili and Ari have managed to get the council to release lots of data on properties and car parking, and they are producing analysis of this data by postal code area and by street. They haven’t managed to get anything on land uses, so I thought, why not produce this with OpenStreetMap data?

A few evenings later, here is the result shared on Google docs (direct link) covering the eight postal code areas that between them cover most of the borough (SE1, SE5, SE15, SE16, SE17, SE21, SE22, SE24):

What the data means

The “summary” worksheet shows the total land area, expressed in hectares (10,000 m2), for various different types of land coverage. I have also calculated the percentage of that postal code area that the land uses represent, which gives an interesting insight into the differences between the areas.

Some of the land uses will overlap, for example miscellaneous bits of green space are often mapped on top of residential areas. So the numbers aren’t supposed to add up to anything like 100%.

The spreadsheet also contains worksheets for each postal code area. These contain a dump of all the objects in OpenStreetMap in those postal code areas, and this is the raw data the summary spreadsheet uses to get the totals.

Flaws in the data

You should use this data with a large spoonful of salt. Here are the significant flaws I have noticed:

Postal code areas are approximate, for example the boundary between SE15 and SE22 should mark the boundary between Peckham Rye Common (SE15) and Peckham Rye Park (SE22). In my data both the park and the common show up in both of the postal codes, because the boundary isn’t quite right. Read down to my method to see why. The errors introduced are pretty tiny in most places (plus or minus a few meters along the full boundary), and probably cancel themselves out for big land uses like residential, but they probably also introduce some significant errors for parks where the boundaries go awry by 20-30m in places. Sadly there aren’t any accurate open data polygons I can use.

Data is missing because OpenStreetMap contributors haven’t mapped it. Of course the easy solution here is to get more of it mapped and up to date! My estimate of the different types is as follows:

  • Allotments: complete for the whole borough.
  • Parks and commons: all major and district parks complete.
  • Misc green spaces: very poor coverage of, for example, large areas of grass on estates, especially in SE5, the north pat of SE15 and SE17.
  • Woods/forest: all major woods complete, coverage of big clumps of trees e.g. on a housing estate or in a park is very uneven.
  • Residential: complete except for SE16.
  • Industrial, retail, commercial: large areas are complete, but small shopping parades, industrial parks and rows of offices are very patchy.
  • Brownfield/construction: patchy across the borough and sometimes out of date as sites are built on.

Data is also sometimes missing because of flaws in the Geofabrik shapefiles, not all of which I have corrected. For example, I noticed they were missing commons so I manually added those in, but I may have missed other land uses. One major omission, a shame given the interest in them, is the humble sports pitch/playing field.

How I produced this

After a lot of experimentation – I’ve never been trained to use GIS tools – I worked out this method. If you know of an easier way I’d love to hear about it.

  1. Prepare the boundary data:
    1. Extract a polygon for the London Borough of Southwark from the OS Boundary-Line data.
    2. Download the OS Code-Point-Open data, open the spreadsheet for the SE area in QGIS and use the ftools ‘Voronoi polygons’ plugin to infer polygons for the postal codes from the centroids. Post code centroids are very dense in the middle of residential areas, so the boundary between SE15 4HR and SE22 9BD is only going to be out by a few meters, but are quite far apart with large parks and commons, so the inferred boundaries get less accurate in those areas. See this map for an illustration of the Peckham Rye Park / Common problem mentioned above.
    3. Merge together postal codes into the areas (e.g. SE22 9QF, SE22 4DU etc. into SE22) by quering the shapefile for all objects with postal codes starting with SE22, then using the mmqgis merge tool to merge them into single polygons. Clean up the attributes so the shapefile just has one attribute for the correct postal code area.
    4. Clip the postal codes by the Southwark polygon and save the result – finally – as the postal codes shapefile for Southwark.
  2. Prepare the land use data:
    1. Download the  OpenStreetMap shapefiles from Geofabrik for Greater London.
    2. Download common and marsh ways/relations using the Overpass API (with the meta flag on), import the data into QGIS using the OpenStreetMap plugin, and save the data as a Shapefile.
    3. Merge together the Geofabrik natural and landuse shapefiles with my Overpass-derived shapefile into one land use shape file using the mmqgis plugin.
    4. Clip the land use file by the Southwark polygon and save the result – finally – as the land uses shapefile for Southwark.
  3. Produce the postal code stats; for each postal code:
    1. Select the postal code, and clip the land use layer to that selected code, saving it as a new shapefile.
    2. Open that shapefile, then save it in a new projection that will be in meters rather than degrees (I used  EPSG:32631 – WGS 84 / UTM zone 31N).
    3. Open the new shapefile, then run the ftools ‘Export/add geometry columns’ tool (in Vector/Geometry Tools) to add two attributes to the objects for the area and perimeter.
    4. Save the layer again as a CSV file.
  4. Produce the stats for the area of each postal code so we can calculate % of the area as well as ha for each land use:
    1. Save the Southwark postal codes polygon in the meters projection, add the geometry columns, and save as a CSV file.
  5. Collate all the data
    1. Tidy up and copy the data from each CSV file into a spreadsheet, then add in the formulae to tot everything up. You’re done!

For reference, some of the totals in the summary work off more than one land use type so here are the categories and the corresponding OpenStreetMap tags:

  • Allotments – landuse=allotments
  • Parks and commons – leisure=park / leisure=common
  • Misc green spaces – landuse=conservation / landuse=farm / leisure=garden / landuse=grass / landuse=greenfield / landuse=greenspace / landuse=meadow / landuse=orchard / landuse=recreation_ground
  • Woods and forest – landuse=forest / natural=wood
  • Residential, industrial, retail, commercial, brownfield, construction – corresponding landuse tags

Future ideas

One obvious improvement would be to get more data in. Perhaps this first analysis will encourage people to help out with that? I have also emailed Geofabrik about the flaws I have discovered in their shapefiles, so I hope those get fixed.

Another thought is to produce the stats by council ward. But given that there are far more wards, I’d like to find a quicker way of producing the stats for each ward (step three above) first.

It would also be interesting to do it by town/suburb, for example comparing Peckham to East Dulwich. But we don’t have any meaningful boundaries for those natural areas. It would be really interesting to do a mass version of “this isn’t fucking Dalston” for a whole borough, using the Voronoi polygons method to infer areas from surveys at thousands of locations around the borough. One day…

Mapping for pedestrians

One of the odd things about contributing to OpenStreetMap is that you have no idea who is using the maps and the data. You spend hours, weeks, months, years even building up a wonderfully comprehensive database of geographic features in the area, all because it’s fun, because you believe in the project’s ideals or you need the data for your own project. But does anyone else use it? It would be depressing if the answer was “no”.

So I get cheered every time I see documents like this:

That’s an excerpt from a presentation by Southwark Living Streets. They took the Mayor of London’s transport advisor around Elephant & Castle to show how unfriendly and dangerous the area is for pedestrians, and illustrated the whole thing with OpenStreetMap. The chap who made this loves OSM, he told me he realised how useful it could be when he noticed we had put in all the footpaths through estates, making OSM the only map that reflects the reality for pedestrians in the area.

It was our coverage of footpaths that led to OpenStreetMap being used by parents challenging a school’s decision that they were outside the catchment area.

I also regularly see OSM used by cycling campaigners, for example this presentation on a cycling campaign that’s also about the Elephant & Castle area.

Then there was my collaboration with residents local to the Heygate Estate who wanted to map the trees that under threat from the redevelopment of the estate. That, I’m happy to say, has resulted in many of the mature trees being protected in the new plans.

So we have useful maps, and powerful tools for community campaigns if there’s an OSM expert about to help out.

But as I wrote last year, there’s a whole other world of data we could be adding, especially for groups concerned with streets that are designed for pedestrians and cyclists.

ITO have been beavering away on lots of amazing maps that show off this kind of data. These are two maps showing the “walkable city” on the left (the blue lines show footpaths and pavements broken up by black roads) and speed limits on the right (green is for 20 mph, orange for 30 mph).

Here are a few in an area I’ve done some work on, just to show what’s possible:

With a few tweaks to the Potlatch 2 editor on the OpenStreetMap homepage, anyone could easily add all this metadata to streets. There are presets for speed limits and surfaces, but not – yet – for sidewalks. If we could get them in – here’s the enhancement request – I think all those community campaigners already using screenshots of OpenStreetMap might just get interested in contributing data.

How great would it be if Southwark Living Streets could print out a special “walkable city” map of Elephant & Castle for their next presentation to the Mayor of London’s transport advisor?

Southwark’s cycling revolution

Those who are inclined to compromise can never make a revolution – Kemal Ataturk

Every day I set off on my bike for a pleasant three mile commute to work. I love cycling around London, it’s cheap and fun, and I particularly enjoy the spring when lots of “fair weather cyclists” swell our ranks along cycle routes.

Much of London is crap to cycle around, but politicians of all colours claim to support a “cycling revolution”. To achieve that, you’d need to make people from all walks of life feel safe – the number one barrier – and make cycling seem pleasant.

Southwark Council did an audit of their roads recently and found that it was impossible to get further than a few hundred metres without using a road requiring “advanced” cycling skills. You need to be happy using “busy roads” with “complex junctions and road features” to cycle to school, to the shops or to work. Not much good, is it?

For a graphic illustration, watch this BBC journalist’s video cycling around Peckham.

The manifesto for a revolution

If we really want a “cycling revolution”, in which grannies and kids and beginners and road warriors all feel happy cycling around London, we need the right roads. Southwark cyclists have drawn up some great policy on road design. They state, right at the top, the need for:

Safe cycling on main roads, whether Transport for London’s roads or borough roads, by wherever possible, segregated and protected cycle lanes which are at least 1.5 metres wide but preferably wider; where not possible, because of road widths or other factors, maximum traffic speeds of 20 mph, well enforced by speed cameras or otherwise, or other safety features endorsed by a reliable road safety audit; and bicycle friendly junctions.

In other words, make it possible to get around on less busy roads, or to get around well protected on busy roads, with road junctions and features that an inexperienced cyclist could navigate.

So you would imagine a council committed to a cycling revolution is putting in cycle lanes, reducing traffic speeds and making sure junctions are friendly for cyclists, particularly on major cycle routes. Sadly, recent decisions by Southwark Council are making things worse.

Peckham Rye west, heading north

This is a stretch of road I use every day heading north into Peckham town centre (map link). It’s not quite on the London Cycle Network route 22, but a lot of people use this main road coming up from Honor Oak, Forest Hill and East Dulwich towards town. It had a 30mph speed limit and no cycle lanes, so obviously needed some work to fit with Southwark Cyclists’ policy.

The council recently carried out some road works here. Can you spot the difference?

Image

They have widened the pavement on the left hand side of these pictures. That’s it. The net effect is that there is less space for cars and buses to overtake cyclists.

The council’s reasoning is that cyclists should share the road with cars here, joining the main stream of traffic instead of hugging the kerb. But the road has a 30mph speed limit. Who cycles that fast? Who is confident enough to hold up a white van man on a 30mph road? Almost nobody, that’s who. Every day I see cyclists weaving through traffic jams and putting up with cars hurtling past at 30mph. My wife, a recent convert to the bike, hates this stretch of road.

As for the pavement, it’s a lightly used stretch that was already comfortably wide enough. If anything, the council could have taken the decision to introduce safe cycle lanes on this road. I would even have supported them nipping a thin strip off the common if needs be, because there is no safe and pleasant space for cyclists on this main road.

Peckham Rye east, past Scylla Road

Cyclists heading south towards Nunhead and Crofton Park get to stay on the London Cycle Network route 22 the whole way down this road (map link). Cyclists heading that way used to face a useless little bypass that separated them from the stream of traffic for a few metres when the road diverged with its east and west branches. Heading west (off the right side of the picture) you’d get cars cutting across you thinking you were going east the same as them. Heading east down the little bypass you’d emerge for a few metres only to find cars cutting across you to turn left into Scylla Road (the so-called “left hook”).

The council decided to improve this by moving the bypass onto the pavement and making it much longer. For me, heading west, it at least makes it obvious that if I’m on the road I’m heading west. People heading east are probably going to use the bypass. I thought it sounded like a good solution. But…

Here you have it. They have made the bypass longer – great – but made it virtually indistinguishable from the rest of the pavement. Can you see a cycle lane? What’s worse, you now come off this lane straight onto a junction with Scylla Road with no clear priority – are you supposed to wait for cars turning into Scylla Road, or can you move off and make them wait? Every evening cyclists and cars get into a pickle with this one. You can just make out a cyclist in this photo, who had to suddenly brake as a small 4×4 pulled right across her.

Long gone is the cycle lane across the mouth of Scylla Road giving cyclists clear right of way.

Peckham Rye east, heading south

This final stretch of road is just a few metres further down from the Scylla Road junction. It used to feature a nice dedicated cycle lane, breaking only for the bus stop further down the road. A pro-cycling council would have removed that car parking and put in a safe cycle lane for people heading north on this cycle route, right?

Image

Sadly, wrong. The council have removed the cycle lane, even though there is ample space, and left the car parking intact. They now expect cyclists to head down a 30mph road without any safe dedicated space.

Apparently most people supported this

In their report to councillors, officers stated that 93% of people supported the changes. This is because the consultation asked for an agree/disagree view on all the positive changes. Several people – myself included – naively said we liked the proposals subject to some changes but these views were simply reported as “agree”.  Their headline figures disguised the amount of disagreement with the details, and with the wider problems people experience.

I put in a Freedom of Information Request asking for the full responses, and got it remarkably quickly. Here are a few excerpts:

There is a major problem with the proposals for junction of Peckham Rye East and Scylla Road. The cycle bypass cars turn left onto Peckham Rye East and then immediate left onto Scylla Road straight across the cycle lane, without properly checking for cyclists. These proposals do not solve this. Cars should be prevented from using Syclla Road and Old James Street as a cut through to Nunhead Lane.

I believe that this is the wrong way to tackle this danger and unlikely to be effective.

I think it is worse for pedestrians that the road will be 2 way at that point with no island, as I think islands make it a lot easier to cross.

We would like to ensure that this scheme seeks to calm these sections of road to 20mph. Given the ambition of the borough for its roads to become 20 mph and especially the borough roads which it controls, we are concerned that there is insufficient calming.

The current designs could make the rat run, speeding and dangerous left hooks more common, onto a road with a church and a primary school.

The designs miss the opportunity to create a more coherent network of cycle lanes along roads that form part of a strategic London Cycle Network route. Currently they stop and start, sometimes with dashed lines and sometimes mandatory solid lines. This creates a confusing and unpleasant environment, particularly for less experienced cyclists.

The lead officer very kindly debated the merits of the scheme via email, and met Southwark Cyclists on site to make some last minute changes that improved the scheme. But the underlying problems in the area, and the tendency to compromise on cycle safety and pleasantry for the sake of cars, were never up for debate.

It’s council policy, so please change it

Since these works were carried out Peter John, the Leader of Southwark Council, wrote a blog post responding to The Times’ safer cycling campaign. He said:

I recognise that if we are going to persuade people to cycle and really increase the number of journeys made by bike, we need to make the routes for cyclists around the borough as safe as possible.

The trouble is that the council’s own Transport Plan includes the very policies that led to these crazy decisions on Peckham Rye, decisions that are being replicated in other parts of the borough. Their rejection of cycle routes and cycle lanes in the Transport Plan even led to the London Cycle Network being airbrushed out of draft local planning policy for the Peckham and Nunhead area.

Until Peter John amends his Transport Plan to reflect Southwark Cyclists’ policies, and delivers similar changes to this planning document, his pledge to “make the routes for cyclists… as safe as possible” will ring hollow. The revolution will continue to be stymied by compromise for the sake of cars.

Problems and possibilities with ward boundaries

Being actively involved in my local branch of the Green Party means I’ve spent a lot of time wandering around carrying a map of a local ward.

Almost nobody seems to know which ward they are in, often because the names are a bit abstract (e.g. “The Lane” in Peckham, which I presume is because “Rye Lane” runs through the middle) or because almost nobody would say they live in the area described (e.g. “Peckham Rye”, which has Peckham Rye Common and Park in the middle and includes areas normally thought to be part of East Dulwich and Nunhead).

Since the Ordnance Survey published open data, including political boundaries, it’s been possible to put this information into OpenStreetMap. I’ve finally bothered to start doing this for Southwark – you can see the results on this nice ITO map.

Unfortunately the default map on the OpenStreetMap homepage draws the names of the wards along the rather nice dotted boundaries, displacing actual road names and leaving junctions that could easily confuse the user. Here are three examples:

You’ll notice I’ve added “ward” to the end of the names to try and help, but it’s not much of a solution. Three different proposals have been put forward on the OpenStreetMap bug tracker (a dedicated map, hide them, make them less bold).

A simple solution to the problem above would be to remove the names; a more sophisticated solution would be to give road names priority, change the text colour to the purple of the boundary lines, and hope Mapnik allows us to offset the labels so you can have the two ward names either side of the line).

It’s a bit of a shame that they create a mess because they’re useful data to include in OpenStreetMap (much like trees, which I’ve asked for a solution to).

For example, the holy grail of software to help us canvass voters would be to connect the electoral register to the OSM database of houses, allowing us to visualise and manage information on voting intentions and canvasser visits by ward on a nice map.

Another useful application could be Nominatim, which could tell you the political boundaries that any chosen OSM-mapped home, business, park or set of co-ordinates lies within.

For now I just need to finish getting all those Southwark boundaries into the database…

Data quality

One other quick point. The London Borough of Southwark boundary was already in the database, but it’s not very well mapped.

It’s really important to know if a boundary runs down the middle of the road, so that homes on one side belong to one borough and homes on the other side to another borough; or whether the boundary is offset away from the road, usually down back gardens, so that all homes on both sides are in the same borough.

Fellow OpenStreetMappers should be careful to put the boundary in exactly the right position, ideally sharing nodes/ways with the actual roads where the boundary goes down the middle so it’s precise and won’t go wrong if somebody adjusts the road position.

Never mind Wonga, use a credit union

Payday loans have been in the news today, with industry figureheads trying to persuade the public that they’re offering the punters a good service. Well, if you’re seriously stuck for cash you need or have loans you’re struggling to service, a much better place to start would be a credit union.

London Mutual Credit Union, for example, is a not for profit organisation that provides ethical financial services to Southwark and Lambeth boroughs. These services include savings accounts, current accounts and loans to people who find themselves financially excluded from high street banks. They have no shareholders, and all their profits are returned to members.

Unlike Wonga & co they are genuinely providing useful services without looking to make a very sizeable profit off the backs of the idiots and the vulnerable.

Anyone struggling financially would also be best off seeking help from the Citizen’s Advice Bureau and checking out the many handy tips on web sites like Money Saving Expert (a personal favourite).

Thankfully we won’t have Wonga sponsoring our public transport network this New Year’s eve. Apparently Boris has gone for a booze company instead, who promise to promote responsible drinking. Cheers!

Why map data sometimes matters

I was contacted recently by a parent campaigning for a local school to ensure its admissions policy is properly applied. Over-subscribed schools like this one are a common source of frustration and worry up and down the country.

Here’s the rub. Which of these two homes would you say is closer to the school, and therefore more likely to secure a place?  By the way, I’m not sure that the location on the left actually is within the catchment area, it’s just a place I randomly chose to illustrate the coming point…

Routes to the school from two locations using CloudMade maps, the home on the right wins by 500m.

Parents at the location on the right were told they were too far from the school. The method they use to calculate safe distances to the school actually suggests that the location on the right is farther away than the location on the left!

Why?

Because they are calculating distances using a model that measures the distance as if you are driving a car. If you try that, you get a totally different result:

Routes plotted for cars to get to the school, the home on the left wins by 400m.

The school’s model uses the Ordnance Survey ITN maps, and apparently doesn’t account for this short footpath at the end of one road. It was pedestrianised 25 years ago.

Happily OpenStreetMap has all the relevant data (and a few minor corrections the parent, Jasia, pointed out to me) so anybody can plot the route to prove the point.

Incidentally, if you fancy showing your support for this campaign download this letter to the governors, sign it and send it to the address at the top of the document.

Southern Fried London hits the spot

Here’s to Jenny Newham’s Southern Fried London, a collection of our finest grease merchants and heart attack hucksters. Thanks also to the weird and wonderful world of the South London Press, one of two locals in my neck of the woods, for bringing the blog to my attention.

I embarked on my own obsessive photo-documentary project with a friend in an otherwise ordinary market town many years ago, snapping photos of ugly gardens in Bedford. For a year or so I couldn’t walk along a street without noting ugly gardens and trying to remember their location. Perhaps a precursor to my mapping hobby?

The project was intended as a loving tribute to the dull places in which most of us live, and a comment on the influence of the endless gardening TV programmes at the time rather than a criticism of the owners. I doff my hat to anyone who makes an effort to do more with their garden than store old washing machines and weeds.

Like Jenny we ended up arousing the interest of the local media, which in turn led to a full page spread in the Daily Mail. We turned down subsequent invitations to debate garden design with TV personality gardeners on BBC Breakfast and Richard and Judy because they obviously missed the point and wanted us to attack the celebs or the garden owners.

It’s nice that Jenny clearly likes the chicken shop fronts, and isn’t just sneering.

My personal favourites aren’t all chicken takeaways, but you can find them on Denmark Hill. It starts with a Pizza Hut, which has been bested by a Tasty Hut just two doors over, followed a little further south by a Tasty House. Who will raise them a Tasty Mansion?

Getting speed limits into OpenStreetMap

I’ve started trying to add speed limits data to roads in my patch of Southwark. Two things made me start looking at them…

First, I go everywhere by bicycle, which means speed limits and London congestion are of very little relevance to my journey times. But I noticed that journey planners like CloudMade’s offer wildly optimistic journey times for cars. Even ignoring congestion, I thought, they can’t be taking account of speed limits, which across London are lower than the national assumptions. For example, most main roads have a 30 mph speed limit and a growing number of roads, residential and main, have a safer 20 mph limit.

The second reason is that speed limits have been a big issue for cyclists recently, featuring in campaigns around issues like Blackfriars Bridge and Southwark’s Transport Strategy.

So here’s a snapshot of our data around Peckham and East Dulwich after a few sessions on my evening commute, using ITO’s excellent tool:

Orange roads are 30 mph, green are 20 mph or lower, grey are main roads without any data; all the minor roads without speed limit data just show through from the background. Getting more roads down to 20 mph will make them much calmer, more pleasant and safer for people on foot and bike.

Not a bad start, but we have a long way to go! I could probably get data out of TfL and Southwark Council. But I’m interested in seeing what I can actually find on the ground, both because the two sometimes don’t match up and because it made me aware of just how varied the signposting is.

With some roads it’s very obvious – it’s a short residential road with a signpost and a huge “20 mph” painted onto the road. On other roads you could easily miss it. Walworth Road has a 20 mph limit, but if you missed the single signpost going either north or south past endless distracting shops, signposts and shoppers, and buses that often block your view, you could be forgiven for assuming it’s 30 mph like most other roads.

Back to OpenStreetMap, it would be good to get better coverage of speed limits. I notice that some parts of the country like Norwich are very well mapped, while London – with the exception of my experiment, Islington and a little bit of Tower Hamlets – barely has any.

One for a winter mapping party, Harry? Or maybe another good reason to get cycling and pedestrian groups interested? I’ll talk to the Southwark campaigners…

Maps, open data and activism on the Heygate estate

Andy Allan’s excellent post on cycle campaigning reminded me to blog about some mapping help I’ve given a campaign group called the Elephant Amenity Network. One of their long-running issues has been the clearance and demolition of the unfairly maligned Heygate Estate, over 1000 council homes that should have been refurbished for council tenants instead of being knocked down for aspiring home owners to move into the area.

A photo of the Heygate Estate in Elephant & Castle, London

One of the best features of the Heygate Estate is the urban forest that has grown there in the past thirty or forty years. But the few remaining residents and local campaigners fear the “regeneration” will see many or even most of them cut down.

Through a friend who is involved with the campaign, I came along to help them map the trees that are there now. Knowing what you have seems like a good first step to saving it.

So I helped them enter the trees into OpenStreetMap using the OpenEcoMaps install of the Potlatch 2 editor, set-up a simple map that shows them as clickable objects on a map, and provided them with a spreadsheet of all the data at the end of the process.

Some other clever bods in the campaign then used a system called CAVAT (Capital Asset Value for Amenity Trees) that puts a financial value on the trees. They estimate the value to be well in excess of £7.6m! Here is the CAVAT valuation laid on top of OpenStreetMap:

I’m glad to say this has become a case study in a recent London Assembly report into the state of street trees in London, which makes recommendations about the need for open street tree data and uses this Heygate mapping to show both the demand for this data and how useful it can be.

Since mapping the trees ourselves, I’ve received a file with all the trees in Southwark from the council with permission to use and share it, which is brilliant. I did a test import in East Dulwich/Peckham Rye, but stopped short because of rendering issues. It would be great to be able to import the lot and see if citizens can keep the data more up to date than the council, or perhaps even collaborate with the council and Trees for Cities?