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OpenStreetMap – Weekly Review

Lint is a tool that checks for errors in C code, taking its name from fuzzy fluff that accumulates around us, getting in our way and making us sneeze. Map’s have lint too; misplled tgs, orphan segments and untagged ways all cause problems when people want to use OSM’s data. Maplint does for OSM data what Lint does for C code, it looks at an OSM XML file and generates an error report, which can then be rendered by OSMarender, giving visual clues to the location of rogue data:

The Maplint Layer In

With the extension of the Tiles@Home server to support multiple layers, Maplint reports can now be viewed at There’s also a plugin for JOSM – JosmLint – that will highlight potential errors whilst you are editing a map, which can be downloaded from here.

Wii have an interesting approach to mapping underground networks developing on the dev mailing list. GPS units are pretty lame underground, and there haven’t been many volunteers to survey the Blackwall Tunnel on foot. A solution being discussed at the moment is to use accelerometers to detect motion and produce a map, specifically the motion sensors that are integrated into the handset of the Nintendo Wii console. The handsets also have integrated Bluetooth, meaning that they could communicate with another device that is connected to a GPS, and through the use of a process like Kalman Filtering, could produce usable results. This is very much a theoretical discussion at the moment – but highlights the inventiveness and resourcefulness of the OSM community. Read more here.

Nick Whitelegg has produced a browser-based editor for OSM data using the new vector support features of OpenLayers. The modest developer begins his mailing list post, “Not that the world needs yet another OpenStreetMap editor…”, if this is what you are thiking, think again. This is the first time that we have had a browser-based tool that can edit OSM-data without requiring the installation of additional plugins, like Java or Flash. OpenLayers is built entirely upon open source Javascript libraries, with the vector editor making use of SVG to render the data. Having another opensource editor on the OSM horizon is bound to accelerate the pace of development of the other editors. OpenLayers developer, Chris Schmidt says that he had planned to start working on an OSM editor in the next few weeks. Its going to be great to see what further collaboration between OpenLayers and OSM can bring.

If you want to get hold of raw OSM data to play with, you probably want to get hold of a Plant dump – a weekly snapshot of the OSM database. As the data in OSM grows in size, planet.osm also grows. The last planet.osm was 3.5GB when decompressed – thats a whole load of XML that has to be shipped around the place each week. Jon Burgess has produced a set of tools that produce a diff – a file that contains information about changes to the dataset, so all you have to do is apply the diff to your existing OSM data to have the latest version. Very nice work.

And finally, just when you think you have the whole tagging thing nailed down, something like this happens:

Read more about tagging streets like this one here

By Nick Black

Want to know if there’s a proposed phone mast or new house to be built near you? Check out the awsome, a simple way to keep track of these things.

To make this magic work, they need tedious bits of software which scrape data off of council websites and put it in a usable form. I wrote two last night… have some spare time? Hack your own together!

The Pragmatic Mapper (part deaux)

My pragmatic mapper post brought some interesting responses so I thought I’d outline it a bit more.

First, the title is a riff on The Pragmatic Programmer, a neat book.

It’s also an explicit riff on Linus Torvalds explicit pragmatism and differences of opinion with the more political FSF. The FSF is freedom for freedoms sake, Linus is freedom because it’s just better. I like the latter.

On the points of does the OS matter, generally, for some value of matter. Of course they do. They’re much like Microsoft. They’re a monopoly, they have lots of money and giggly lawyers and everyone hates them. They also have maps of the whole country. But do they matter to me, personally, or many OSMers? No. The political side and bringing down The Man doesn’t really motivate me. We make OSM because it’s better and cooler.

I do find it interesting that the responders think that a national mapping monopoly is somehow a good thing. I fail to see how this is different from a national monopoly on tea bags or cars. It seems that the argument is that the OS is relevant because it has lots of data and we could use this (pulls rabbit out of hat) in a flood emergency. Bit of a poor use of a lot of money just for that. Anyway, to respond to points in turn;

…I want someone to organise data cross the entire country. I want to operate a business dependent upon that consistency.

Thats fine, but you don’t need a NMA to do that. You could have regional agencies with individual contracts where an overseer body puts it together. You could, god forbid, use OSM when we’re there. On an economic note, even if you want all that, and you want an NMA that’s fine, just please don’t force me and the 65 million other citizens to pay for it as we might not want it.

…I want to know that environmental policies in the north and south are based on similar data, its analysis and methodology and applied fairly.

Cool, but still don’t need an NMA for it. We have policies in the north and south are based on similar data, its analysis and methodology and applied fairly in schools, hospitals, roads, universities, water, gas, electricity…. most of these just need an overseer not an NMA.

…In the case of an emergency, I want to know someone can put together a river network and all its tributaries and work on solving a hydrological problem effectively, if there is a need.

Still don’t need an NMA for that. Being a bit hardcore, the emotive issues of ‘think of the children!’ or ‘what if we get flooded’… well the insurance market is very clear about that. Don’t live in a flood plain. If you want amazing disaster recovery maps of your area, then pay for it but please don’t force us all to. We might want to, of course, just don’t force us. And Katrina is not a good example, the federal government distorts the market by forcing flood insurance through FEMA. It’s the same argument as keeping rural post offices. If people in the countryside want them, then pay for them. There’s no god-given right to maps and post offices.

…I want someone to survey and record the entire country in case I want to visit other parts, know what is there and understand where I can go.

What do you do when you go to the united states then? The country isn’t falling apart because they have different mapping providers in different parts of the country. I can find my way around Orlando and San Francisco just fine, despite them being thousands of miles apart and one with a map from Hertz and the other from the county sheriff.

…I want an agency who supports governmental operations in a neutral manner with spatial information.

So do I. It need not be a country-wide monopoly. And the OS are far from neutral. By definition they stifle competition and progress, without even waving around OFT reports.

…I want someone responsible for ensuring the education system produces infrastruture and knowledge to people so the geography of the land is know, recorded and stimulated.

University Geography departments would not be impotent without the OS. 11 year olds can still learn about geography without a free map.

I wonder if Openstreetmap honestly feel that they are ready to provide disaster response mapping, or have the resources in place to ensure that their coverage of the entire country is current to within one year or less.

Not yet, but we or someone like us will. And anyway, you don’t need an NMA for disaster response mapping.

It’s perfectly fair for OpenGeoData to think that Openstreetmap suits his mapping needs, but to call it superior, and to say that the Ordnance Survey is irrelevant is a little short-sighted.

Navteq are letting you submit errors and so are teleatlas with map insight. Our way of making maps is most definitely superior and it’s the future.

If you can, listen to this podcast which excellently summarises The Wealth of Networks.

To come back to the original post for a second, really the pragmatic point was to say should we spend our time campaigning against the OS, or just building our own systems and maps? Campaigning for open data from the OS, or change to government policy is just sticky tar. Would we have got anywhere in the past two and a half years by just campaigning? It’s very doubtful. We’d have publicity no doubt and a few more high-placed friends and enemies… but this way we have that and a mapping system, and a community of 5,700 people, and maps of Baghdad, and vast sections of the UK mapped.

I have some idea of what I’m talking about here, as I’ve been involved to varying degree with fipr, no2id and stuff.

But one thing I think would be cool to do is make a map of map charges. The idea is that the OS basically don’t respond to awkward questions through the Freedom of Information Act as they’re commercially sensitive… but if we all write to our councils and ask them then they have to give us at least some idea. My council just sent me a letter with the new council tax bill breaking it down by police, schools and so on.. but not maps. So, we can figure out who’s paying the OS too much or little. It’ll be interesting. What you need to do is find your council website and information freedom officer and write them a letter asking for this stuff. There’s a wiki page with a sample letter to help you get started.

As far as I know this data doesn’t exist anywhere.

Another Week on the OSM Mailing lists…

Happy first birthday to Osmarender. As Blackadder/Andy Robinson pointed out this week Osmarender is now a year old. Before Osmarender there was nothing that generated maps from OSM data, and right from the start it performed well. Over the year Osmarender has added support for layers, areas, symbols and bridge/tunnels to give the Osmarender we have now. Compare the two maps below of Weybridge from the first to the latest incarnation of Osmarender. Also, Osmarender is the rendering engine in the times@home project which turns round updates to the map very quickly. It will be interesting to see what the next year will bring. Great inspiration Etienne & great work to all the collaborators ….

Weybridge by Osmarender

Mapping and rendering tunnels came to the fore this week with Steve Chiltern starting a discussion around just how do you really map out a tunnel (the astute of you will realise that GPS coverage is not the best in a tunnel). Various solutions were proposed with video-based surveying & inertialmeasurement units sounding promising. Not sure about the wire-guided missile idea though! Mind you, with a tunnel engineer amongst the OSMers some progress should be made. The issues of layering and tunnels was also covered here.

The question of how to get tiles updated on the map seems to come up again and again. Well, for the Osmarender view go to zoom in to level 12 on the area you want, and click ‘request update’. There’s talk of getting this implemented as part of the slippy map too. On the dev list there is discussion of a JOSM patch to allow the same kind of thing.

A great discussion kicked off by Andy Allen on tagging MBR trails (Ed: he really meant MTB trials). Should they be covered by a route tag? Should they be given grades? Should there be an ascii-art description of the route surface ( nnn=cobbles, __~~~___=flooding etc.). Looks like there will be crossover from the MTB community to get some mapping done. Great!

SteveC’s thread on Finding new stuff while mapping points to the joy of getting out on the road. Being ‘forced’ to go down every lane/track/path brings out lots of things you’d probably never noticed about your local area. So what are you waiting for? Get out there & see your place in a a whole new light!

This gets my thread-of-the-week award: The set of problems thrown up by the question of maximum segment length by Scott Walde. It started off by problems with things not rendering properly and segments being missed because the start/end of the segment was out of the area being rendered (though it did cross the area). Adding a point in the area ‘fixed’ this. Being a global discussion it brought up a whole range of issues on road networks – a 50K straight road is not uncommon in some places, as are grids of roads running north/south & east/west. And what happens with different projections – well worth a look. So how long is the longest stretch of straight road in the world?

There were a few things of general note on the dev list this week. Thomas Lunde brought up the US TIGER import problem. TIGER is a database of all the streets in the USA. Lets say that again: TIGER is a database of ALL the streets in the USA. And there are no copyright restrictions on using the data. Handy eh? There was an import of the data running for quite a while, but it had to be purged because of data cleanness problems. A new version of the TIGER data has come out (as of the 6th March) and there is discussion of re-running the import, and how best to do this given the existing mapping that has happened in the USA. Separately on dev Andreas Voltz asked about Writing an OSM map application and received a bunch of useful information about OSM data & appropriate databases.

The number of mapping parties is growing like topsy. Last year there were seven. There are three this March, and ten so far either happened or planned this year to June. These parties have given step changes in the mapping around Manchester, Bath, Reading, Brighton, The New Forest, VāsterÃ¥s, Rutland, Munich, Val Thorens, London, Toronto, Bristol, South London, Amsterdam (last weekend), and planned for Sheffield, Karlshrue, Madrid, Southampton and North Wales. This doesn’t include the recent funding where 12,000 euros have been earmarked to subsidise another ten mapping parties in the Netherlands this year. Way to go!

Don’t forget: If you want to submit something to OSM’s State Of The Map Conference, you had better get your skates on. The closing date for submissions is the 30th of March.

Legal-talk has been strangely quiet this week…..

by Barry Crabtree.

State of the Map 2007 – Conference Update

Preparations for the State of the Map 2007 is in full swing. Head over to for the latest news, including a preview of some of the talks and workshops planned for Manchester in July.

To be kept up to date with the latest announcements, you can subscribe to the State of the Map feed, or email to be added to the mailing list.

A week on Open Street Map Mailing lists.

Mailing lists are great. Don’t you just love it when an innocently titled OSM layer into Adobe Illustrator post breaks out into a storm? Phil Barnett, who wanted to use OpenStreetMap data along with imagery from Google Earth in an ITN news cast asked, “…and I presume there’s no problem with broadcasting this composite…”. There followed plenty of IANAL (I Am Not A Lawyer) prefixed comments, but the crux of the problem is this (from Mike Collinson) – OSM needs to make it crystal clear what constitutes a derivative work from OSM data, otherwise all this fantastic content is not going to be used to anywhere near its full potential. The debate continues on the Legal Mailing list.

If you are thinking of getting involved and wondering what type of gps unit to get (Tom-tom? Garmin? ….) take a look at the disucssion promped by David Stevenson on which sat-navs log, which specifically discusses Tom-toms, or look at the advice on the freshly updated wiki. That should give you a good round up of the pros and cons of the different devices that are around and set you off in the right direction (groan!).

The open tagging system that OpenStreetMap adopts always causes a lot of debate. This week, David Earl tried to finalise a new set of tags that the community have almost agreed on, which soon became a village-green discussion and a plea from Ben Robbins to be less flame-war-ish – its about critical discussion – don’t take it personally. It turns out that, village greens are not commons. OK, true enough but do you really care? Get off the fence and join the great OSM tagging debte. How exactly do you tag a fence?

A great subway-station vs. subway entrance discussion kicked of – do you put a node where the subway is, or mark each of the entrances? The weight of opinion was that you mark all the entrances, with the view that the routing/rendering engines will do the right thing and produce a detailed map. This does the discussion so much injustice – as with most of these kind of things, the devil is in the detail. Check here for the details.

There was a good talk about presenting the splippy map starting from other locations than Europe – country/IP based mapping was discussed, as was a view of the whole world (you know, sometimes the simplest solutions are the best 🙂 ).

Don’t you just hate it when…. opened up a vein by Nick Whitelegg to vent all those frustrating things that can happen once you start that addictive thing called mapping. If you do nothing else today just read the thread. Did you really spend a few hours mapping and forget to check that your gps was logging? Wasn’t it really frustrating when your train took a detour down all these new unmapped tracks and the coating on the windows interfered with GPS reception. I was on the floor by the time I read Ivan Sanchez’s comment! You need to go there… I’m waiting for an OSM-dev version to appear….

Osmarender4 has been up and running for a week or so now – (beautiful bridges) and should be running on all tiles@home clients now. There are a whole new set of icons as well. Looks like there will be some occasional confusion with the tiles on the slippy map util they are all osmrender4’d.

Looks like an Amsterdam Mapping Weekend is on the cards for the 17th/18th March. Who’d want to go to Amsterdam eh? 🙂 The things we’ll do for our art!

Oh, and we made it to the UK East Anglia Evening News, or David Earl did with an article on his and other OSM contributor’s great efforts to cycle and map the whole of Cambridge. There’s a brief item here.

By Barry Crabtree