Access Land

Snowdon has experienced flurry of edits on OpenStreetMap after the last two long weekends. I happen to be one of the culprits as I've been adding some detail from last July: not least because a family member is planning an attempt on the Welsh 3000ers next month.

The availability of Bing aerial imagery allows a lot more detail to be added, particularly when I can relate it to geotagged photos. I've been able to add:

• walls and fences alongside or crossing tracks;
• bits of marshy ground;
• extend paths which I saw, but didn't walk;
• and, correct alignment of streams and rivers.

In doing so I've also noticed quite a few things which I recorded but had not transferred to OSM: notably stiles and gates.

Whilst looking at these photos I noticed one of a stile had a roundel indicating the start of Access Land. I've suggested before that it's worth mapping these locations as the complete area covered by access land is only likely to be worked out through gradual accumulation of access points. However, when push comes to shove, I'd not done it myself and couldn't think of an obvious tag for it.

I also found a photo of a large notice for the area, Glyn Rhonwy. This contains a lot of old slate quarries including one huge hole. The notice states that the upper part of the area is access land. However the stile we went over when we came out of the old quarry area had a rather threatening warning notice. This appears from the Ordnance Survey mapping to be exactly where the Access Land starts.

There was another puzzle on the edge of Llanberis. We wanted to avoid walking straight down the road, so had aimed for a footpath marked on the map leaving at a corner of the road above the tea shop at Penceunant Isaf. Checking the OS map today I see that this is also Access Land. All we found was a firmly locked gate.

All in all the Access Land areas in Snowdownia are not that well marked, and are often huge: making them poor targets for mapping. In most cases they're fairly obvious, or are areas where access has been presumed for many years, so adding them to OSM is not a huge help for the walker. Closer to towns and villages there still seems to be plenty of ambiguity. I'm not a fan of the huge intrusive notices that do exist either. They seem inappropriate in a National Park.

Although I added a lot of detail in Snowdoia, I needed to find somewhere else to look at mapping Access Land.

The one place I have been in the past couple of years which is access land and where I probably have enough information to map access land is Parkhouse Hill. This striking little hill, one of a pair of fossil coral reefs (the other, Chrome Hill is shown above), lies just inside Derbyshire in the upper reaches of the valley of the Dove. It is also one of the places which was pretty inaccessible until Access Land was introduced by the 2000 CRoW act.

I took a whole series of photo from the ridge of the hill in September 2009, but without good aerial imagery it was not possible to delineate the outline of the accessible area. Only when writing this post did it occur to me that I could now complete this mapping. Accordingly, I've mapped the access land itself as a relation, and added the tag entrance=access_land where I recorded the relevant sign. The tagging is still pretty tentative, but I hope having something concrete will lead to a common approach.

Radburn : exemplar or nightmare

Radburn is a small community in New Jersey.

View Larger Map

Until a few weeks ago I'd never heard of it, but at a friends party we got talking about The Meadows area of Nottingham, how it's changed and how it might change again. The council plan to partially revert the area to a gridded layout and reintroduce a linear shopping street. The area as it is now consists of many short cul-de-sacs off orbital distributor roads, with many houses accessed along paths or through communal green space. Radburn, NJ is the archetype for this type of layout.

I have been mapping The Meadows in a desultory way now for a while: it's not the best part of town so I like to keep mapping visits fairly short. The areas which were re-developed in the early 1980's have an amazing complexity of footpaths, and short side roads. Varying height buildings also sometimes contribute to a canyon effect with the GPS, particularly in the parts which still consist of late 19th century terraced housing.

The Meadows were originally the water meadows of the town of Nottingham, famous in the spring and autumn for displays of crocuses (Crocus vernus in Spring and C. nudiflorus in Autumn). These non-native plants are supposed to have been introduced to the Nottingham area by the monks of the Clunaic Lenton Priory. They still survive in various sites in and around the city (for instance the General Cemetery, Waterloo Promenade, University Park). The area started being developed after the Nottingham Enclosure Act of 1845, when certain parts of the area were dedicated as green spaces (e.g., Queen's Walk). The remainder was largely developed as high density terraced housing with some small scale industry. A colliery opened by the River Trent around 1910, followed by a council-owned power station (both now the site of a retail park). This was what led to the story of an ignorant DJ introducing a request with "Crocus Street, The Meadows. What a lovely address!".

By the 1960s this was one of the areas the council was anxious to re-develop in what were then known as slum-clearance programmes. The whole western portion was demolished in the mid-1970s, to be replaced by lower density housing with much more green space and small gardens for most properties. Additionally, private developers also built housing in this area. The remainder was re-developed piece-meal with the larger original houses being kept smaller less salubrious places being replaced. This accorded with changing planning fashions, with 'cellular renewal' replacing big bang clearance projects. Probably this was because by the late '70s it was clear that there were problems with many of the replacement buildings of the 1960s.

What staggers me is that now, thirty years later, the council wants to 'regenerate' the area. Apparently, its problem is all to do with the Radburn layout.

View Larger Map

One of the great things about worldwide on-line maps is that we can look at places as far apart as New Jersey and Nottingham in a similar way. On OpenStreetMap the cartography is the same worldwide too. This really brings home the differences between the real Radburn, and "Radburn", the planners concept.

The Meadows is obviously much more densely populated: it has a highly convoluted network of paths, whereas in the Radburn the purpose of each path is pretty clear just from the map. The green spaces are smaller, and less connected too. However, The Meadows housing is far pleasanter than its predecessors and the green spaces do sustain a decent amount of wildlife.

I also, doubt if Radburn has a deeply obscure house-numbering scheme, with houses on the same road having different streetnames. Some named roads don't have any addresses associated with them at all.

There are plenty of other places in the UK which are tarred with the now tainted "Radburn" name, like Oxmoor, Huntingdon, a suburb of Havant, suburbs of Telford such as Woodside, Dunclug, Ballymena (NI), and Deanbank, Penicuik (Scotland). Many of these bear only a tenuous resemblance to the original: a planning concept having been transmitted by chinese whisper. Some of the problems are glaringly obvious when one tries to map these places: its difficult to determine addresses, there are far too many paths around the back of properties, few shops have survived, the green space is festooned with "NO BALL GAME" notices. BUT, just as these designs were a planning fashion, it looks like denigrating them is one too. It seems too easy to lay the blame for problems in these areas on the original planners and architects, rather than understanding them as aspects of more complex social issues.

In case of The Meadows, the money for its has 'regeneration' disappeared in the great wave of government cuts. Perhaps this will lead to a more incremental approach, rather than the traditional waving of the planners magic wand to fix social problems.

Catmose Campus : an Oakham update

On the way back from Barnack I diverted from the Oakham ring road to go and check how much of the Catmose Campus was open. I mapped this a few days before its scheduled opening in February, so it was good to have a simple quick mapping objective.



It proved that my quick photos taken in the rain were not a very good guide to the actual location of the building (compare with the actual GPS traces in this screen snapshot):

As I walked up to the entrance to the Sports Centre I reflected that at some stage most mapping should become like this. A short stop off to grab the new details of the changed area, and a quick and simple edit session to finish off. We're a long way from that point, but before we get there we'll need better ways to identify areas with changes and to manage checking their status.

All-in-all a more satisfying mapping experience than last time I was in Oakham: the weather was nicer too.

Along the Fosse Way: mapping a new road

A46 road works, East Stoke : 3562a, a photo by SK53 OSM on Flickr.

The A46 between Widmerpool and Farndon (near Newark) is being reconstructed as a dual carriageway and is due to open next year.

Kev Swindells has done a great job mapping the southern section of these road works to the junction with the A6097 at East Bridgford. Several sections are already in use, and once again OpenStreetMap is more up-to-date than other online maps. The most obvious of these is the big new roundabout West of Bingham (below, also compare with Google Maps).

View Larger Map

At our first pub meetup in Nottingham I asked Kev he was going to do any mapping North of East Bridgford, but apparently its beyond his normal bike runs. I'd already taken some audio notes last summer and had marked in a new overbridge near Elston. So on a nice spring evening I decided to see how much information I could collect for the remaining part of the route. I tried to cross the line of the road works on as many minor roads as I could, starting from Newark and working my way back towards East Bridgford.

Even with decent waypoints for the crossings it's not straightforward to get the rest of the alignment. Several things do help:

• Powerlines. Lots of powerlines cross the Trent S of Farndon, and all have been mapped (from surveys, Bing and OS OpenData). From photos I can check how the road alignment compares to pylon positions.
• Field Boundaries. Most field boundaries visible on Bing are still there: obviously they've gone along the construction zone, but again it's useful information.
• Hedgerow Trees. The farmland on the E side of the Fosse Way towards the River Devon has little in the way of trees and no patches of woodland. Each large tree which can be located on a photo can be matched to the Bing imagery.
• Aerial Photography. In a couple of places the Bing imagery is recent enough to be able to see that the ground has been cleared in preparation for construction. This was particularly useful just N of Flintham close to the point when the new road crosses the old road (nothing on the ground yet: presumably this will be the last phase of construction.

This mapping is very preliminary: Kev mapped the Southern section in multiple visits by noting where the roadworks obstructed cycleroutes. Ideally more of the local minor roads and footpaths could be mapped to add to the detail as the road nears completion. This is particularly true near East Bridgford. The precise location of the two carriageways is also not clear: round RAF Syerston it looks as if the cutting is not completely excavated yet.

I didn't forget to collect other data: the little village of Syerston was missing all its roads. It has a nice little church too. I was able to do a bit of general tidying up of the other minor roads. Another nice church, which was already mapped is at Hawton: this has a very fine Easter Sepulchre in the chancel. Both churches are dedicated to All Saints.

Leafy St Ann's : pre-pub mapping

Despite it being just after Easter and the date being announced with only a weeks notice, there were 6 of us at the second OSM pub meet-up. This time we met at the Lincolnshire Poacher on Mansfield Road: definitely a pub worth of the real_ale=yes tag.

With lighter evenings it seemed worth doing a bit of mapping before having a drink: also a good opportunity to show people the ropes. I chose the Poacher, not just because its a nice pub with good beer, but because there are quite a few places in the immediate vicinity which could do with more map survey work. These include the Arboretum, Church Cemetery, also known as the Rock Cemetery and residential areas either side of Mansfield Road.

I'd done a bit of preparation for each of these, but once I realised that there'd be enough of us I persuaded people to visit St Ann's. Although this inner city area has a poor reputation I knew a decent route, and it offered a much more varied insight into the issues associated with collecting data for OSM.


The main mapping objective in this area was to fix roads with missing or, possibly, incorrect names. I had made a print out (see above, and here registration required) from ITO OSM Analysis which provided the basis of a reasonable hours mapping. We walked a loop down behind Huntingdon Street, along St Ann's Well Road and then along the tree-lined walks of Robin Hood Chase, Corporation Oaks, and Elm Walk back to the pub.

St. Ann's is predominantly 1970s and early 1980s social housing: the area having been re-developed as part of a slum clearance programme. It was planned with a 'Radburn' layout : lots of cul-de-sacs and interconnecting walkways. Addressing and street names are really confusing as we immediately found out. We walked through a twitchell from Huntingdon Road and found houses with addresses on Sherwin Walk, but we were looking for Sherwin Close. On the opposite side of the road were houses on Welbeck Walk, with Welbeck Close already mapped on OSM. This seems to be typical throughout the area: house addresses are slightly different from the streetname. In addition there are groups of houses which have a separate address, but no linked street: Rodel Court was one I noticed as we crossed Abbotsford Drive.

Once we turned onto St Ann's Well Road everything was much greener. The road itself is tree-lined, with lots of grass between the road and housing. We popped up one road (Instow Rise) to pick off a few street-names and came across another big green open space. Back on the main road I noticed a pair of Mistle Thrushes flitting about.

The real surprise, for those not in the know, was Robin Hood Chase: this is part of a series of green spaces preserved when the Nottingham common land was enclosed. This included the Clay Field an open field dating from mediaeval times, which covered the area which is now St Ann's. Although most of the land was very rapidly developed, a good proportion was retained. In recent years this wise decision has been marked by the Nottingham Enclosure Walk on the last Sunday in June, which takes a rambling route through the parks and gardens created as part of the Nottingham Enclosure Act. At the top end of the Chase there was an old cast iron notice stating that the council had not dedicated it as a highway. I presume this means that access rights are permissive, but more research is required. (It's worth noting, perhaps, that Robin Hood Chase does not appear on other online maps).

I forgot to take any photos so I've borrowed one from Geograph, and grabbed one from the 2009 Enclosure Walk. These give a reasonable idea of its role as a green lung.

Looking up Robin Hood Chase
© Alan Murray-Rust CC-BY-SA.

We managed to add or correct around 10 street names, but we noticed a lot of other things. Here's a non exhaustive list of the various other objects which got mapped from this session: traffic tables, speed limits (20 mph zone), access restrictions, traffic calming measures (cushions, humps, bumps, chicanes), pedestrian crossings, cycle parking, an ATM, shops, restaurants & fast-food outlets, an old cinema (see picture), churches, a few house numbers, post boxes, telephone kiosks, bus stops, a green roof, and a dead pub. This diversity is good for an introduction as most of these only require a node adding to OSM, so its possible to focus on tagging. Cycle Parking was the immediate attention grabber as there was no space at the back of the pub for a second bike: not only was the first cycle stand we came across mapped, it was used too.

There were also a few things which didn't get mapped for sundry reasons: solar-powered parking meters, hand car-wash in the former pub car-park, a SureStart children's centre, and the East Midlands Anglo Chinese Society. In the main this is because I don't know how to tag them: but hand car washes in derelict filling stations and pub car parks are becoming such a conspicuous feature of the contemporary urban landscape they probably deserve notice.

In the pub we talked quite a bit about OpenStreetBugs: David and Marcus both seemed keen on the idea of being able to mark-up things requiring mapping as an entry-level way of contributing. Kev showed how he was using OSB to mark cycle parking. David commented that he'd want to be able to filter by a category such as 'cycle infrastructure'. We briefly talked about KeepRight as well.

This led on to David's observation that he felt that quite a lot of existing cycleways were overly generously tagged. Kev agreed and remarked that he'd recently removed a lot of cycle tags on roads in the city centre: partly in response to change signage, but also because the original mapping was less than useful for cyclists. This is definitely a theme to follow: getting some in-depth feedback on what is mapped from potential users is not particularly common with OSM. I'd like to see what we can do in this direction with the Pedals membership.

This naturally led onto the Nottingham Hackspace. Last month Marcus suggested the Hackspace would be a good place for an OSM event. I went along the following open evening to see the Hackspace and meet its members and have been thinking about what we can do together ever since. But early in April the Hackspace's landlord lost its tenancy, and I've been following the saga of finding a new space. This was finally resolved only on Monday: the new space is huge and located just to the east of Sneinton Market. I only hope there isn't a plan to move every month requiring a re-map of the space and its surrounding area.

Thanks to everyone for an interesting evening. Once again I find I'm learning lots by talking with people less familiar with the intricacies of OSM.

Lastly, I've set next month's date for 24th May back at the Lincolnshire Poacher.

Is a research paper on OSM a derived work?

In a long an insightful blog post on Google MapMaker's US launch Mike Dobson mentions a paper by Girres and Touya. According to his blog this paper uses a similar approach to that of Muki Hakaly to analyse French OSM data. I'd like to read this paper, and consider its implications : after all I've contributed to the data that it has used. However it lies behind a pay-wall here: Girres, J.F. and, Touya, G. (2010). Quality Assessment of the French OpenStreetMap Dataset, Transactions in GIS 12(4), 435-459.

I didn't find an electronic offprints at the researchers lab site: IGN COGIT. If anyone knows where I can get a copy let me know.

I would regard it as a normal courtesy of scientific publication to give contributors access to paper based on their data. Certainly the derived data which underpin the work should be made available as Hakaly does, but it's the overview and conclusions which are of most interest. However, I'd like to pose the question: Should this work have been published under CC-BY-SA?

Old Ballparks and other Stadia

Recently it was noticed that the baseline at Yankees Stadium had been added as a oneway footway on OpenStreetMap. This triggered a discussion about the minutae of the game on #OSM. Now, much as I love baseball, I'm pretty hazy on the fine points of the rules, and, indeed, terminology. This is pretty much because all of my knowledge was garnered as a third-grader a very long time ago. I only ever saw two MLB games live (box scores here and here), both at the long vanished Forbes Field.

This prompted another rumination about the geography of vanished bits of the social fabric (which seems to be a developing theme on this blog).

In Britain and the States a huge number of sports stadia were built at the start of the 20th century. When I was growing up these places had a suitable romantic patina from age and great sporting exploits: a romance which belied their often smelly reality (John Bishop is very good on this). By the 1960s even with a modest amount of investment they were becoming rapidly superseded by social change. Many were difficult to maintain, were no longer suitably located (particularly when fans started coming by car) or had more profitable uses.

Cheaper air transport drastically affected Major League Baseball: it was no longer necessary that all the MLB franchises be within an overnight train journey of each other (discussed and mapped in "Spatial organization; the geographer's view of the world" (Abler, Adams and Gould (1971) pp. 377-9). So in the late '50s the Boston Braves moved to Milwaukee, the Brooklyn Dodgers to Los Angeles and the New York Giants to San Francisco. Although franchises had moved a bit before that time, it ushered in an era where owners could extort subsidies from local tax payers by threatening to move the club. Yet in many ways the more modern stadia were a false start. The multi-purpose stadia built in this period ('cookie-cutters') have now being torn down and replaced by separate parks for baseball and gridiron. That great novelty, an indoor ballpark, the Houston Astrodome is now a mouldering, crumbling safety hazard. Perversely more recent ball parks have tried to capture the feel of the early 20th century Jewel box parks.

In Britain change came later, and in response to several fatal disasters which highlighted the poor safety arrangements of many of the older grounds. As a teenager I watched games from cinder-covered terraces, or seated in wooden fire traps like that of the Bradford fire. Notts County's 1910 Meadow Lane ground even had a stand which was older than the ground, having been transported across the Trent from the county cricket ground.

These are the English Football League grounds which have vanished since I watched a match there : Filbert Street (Leicester), the Baseball Ground (Derby), Saltergate (Chesterfield), The Old Showground (Scunthorpe), Fellows Park (Walsall). I'm not particularly nostalgic for any of these, as a kid it was often difficult to get a decent view, the loos were laughable, and as we learnt, safety was poor. Filbert Street was a disaster waiting to happen: we 'watched' a game in such a crush that my father was so fearful of our safety that he hoisted us to the top of a wall away from the crowd. Variously these are supermarkets, housing developments or still brownfield.

However, the memory of great sporting drama at such vanished locations lives on in the memories of thousands of people. Over the past few years, The Observer has run a fascinating series of articles on the fate of a whole range of stadia after they ceased use for sport. These often managed to illustrate the intricate relationship between sport, economics and (urban) social fabric. Unfortunately these pieces don't seem to be available on-line. There are plenty of websites devoted to the subject: e.g., Old Grounds, and Aerial Lost Stadiums. Wikipedia's articles on the subject are usually detailed and thorough.

Stadia like many other historical sites are problematic to map on OpenStreetMap. When some fabric remains, then it's usually possible to tag this in such a way so as to indicate its original purpose. Adding single nodes for the former site (as the imported GNIS node does for Forbes Field) is probably acceptable, without challenging OSM's absence of a model for historical mapping. Culturally, the sites of old stadia might elicit wider interest, than, say, sites of battlefields.