OpenStreetMap: Free Software’s Answer to Google and Commercially Restricted Geodata

By Gary Richmond

osm Ed. note: This article originally appeared in Free Software Magazine.

In a recent article on free software and the Large Hadron Collider I mentioned that here in the United Kingdom The Guardian, a national British newspaper, had founded a campaign called "free our data". They objected to the fact that the Ordnance Survey (and others), funded by the British taxpayer, was charging business and individuals for its cartographic data thus effectively making people pay for it twice. Their campaign is great but until such times as it succeeds an alternative is needed. A free software alternative. Enter OpenStreetMaps.

Google Earth and Google Maps are too well known to require iteration here, but the spectre of proprietary software haunts them. They are not free software. If you want to incorporate any of them into you budding business project and run your software under a relatively permissive licence for others to take up your ideas and improve them you will have to find something else.

Just like Wikipedia, on which it is loosely modelled, OpenStreetMaps is resolutely free software. It is an attempt, by community participation, to map the Earth.

Well, it's nothing if not ambitious. Google do it but then they do rather have a lot of money to fund such a global undertaking. Doing it on a shoestring with community volunteers is quite something else but then this has never deterred the free software community. Hence the need for what has been called "citizen cartographers". It's all relatively, marvellously, low tech: Archimedes claimed that if he had a sufficiently large fulcrum he could move the Earth but all you need to map the earth is a GPS-enabled device, a car, a bicycle, motorbike or just a pair of good old fashioned legs to track, record and then upload the data to OpenStreetMaps' servers. It's a Micky Rooney/Judy Garland moment. Those pesky adults are being difficult spoilsports. Hey kids, let's put the show on ourselves in the backyard! That was the thinking of Steve Coast, OpenStreetMap's founder. He realised that most of the available mapping was done either by private companies and government agencies who restricted access to their cartographic data or charged expensively for it. This is a problem particular to the UK.

OSM's got a tiger in the tank
In the USA the Census Bureau is required by law to make the data freely available and they have in fact released a set of imagery called TIGER, an acronym for Topologically Intregrated Geographic Encoding and referencing Systems, into the public domain. This huge data set means that there is little incentive for volunteer citizen cartographers to get on their bikes but it does have two distinct advantages: because TIGER does not operate under the restrictive, proprietary business model of the UK's Ordnance Survey the data is freely available. Also, given the fact that the USA is approximately forty times larger than the UK with a relatively lower population density, mapping the USA OSM-style would not have been so much a Herculean task as a Sisyphean one. OSM have been able to load that huge geo-database to their own servers using a conversion script to convert data to an OSM-compatible format. It is a mammoth task running night and day (from August 2007) and was due to complete in June 2008. I checked the OSM stats and the upload has completed. In fact it completed months ahead of schedule. Thankfully, and in the same vein, AND donated a large set of street maps covering the whole of the Netherlands as well as the highway networks of China and India. Surely, it can't be a coincidence that Google started with free software and free data. The principle that knowledge wants to be free is not only a good one but ultimately it can lead also to innovation and competition.

Although the solution to opening mapping was a response to a particular problem in the UK, OpenStreetMaps has morphed into a global undertaking. If you go to the frontpage of the site you will see a list of events which covers mapping enterprises right across the globe: France, Chile, South Africa and Germany to name just a few. The term "mapping party" may become a familiar phrase like "flash mobbing" - but more useful and significant. So, if you happen to spot cyclists armed with GPS devices they may not be navigationally challenged but scouts and emissaries for OpenStreeMaps. (It has just occurred to me that the famed LUGS [Linux User Groups] could be used as a template for mapping parties. They have an existing structure and body of expertise which could be exploited to fastrack the whole business!)

Five easy pieces. Sorry, steps
OSM has made the process of map making easy under the rule of five: gather, upload, edit maps, edit data and render maps. Voila! One of the best things about OpenStreetMaps is that it does not require any special plugins: it will run on any browser as long as Javascript is installed. The "slippy" map you see is powered by an Ajax component. You can use it inside a browser as you would do with Google Earth and Google Maps.

Can OpenStreetMaps link and integrate to anything else?
Like Bob the Builder, yes it can. Let's look at three "mashups": Flickr, Marble and Nestoria. Geotagging is very Web 2.0 and this represents a golden opportunity for free software like OSM. If you are going to embed geographical information in the metadata of photographs, it makes sense to do it the free software way and modify according to your particular needs. This is exactly what Flickr did. They do use Yahoo Maps but decided to use OSM where Yahoo's maps lacked detail. This was reciprocity of sorts as Yahoo has donated aerial photography to OSM in the recent past. As a result of OSM being released under a Creative Commons Attribute-ShareAlike 2.0 licence Flickr incorporated OSM and debuted it with a spectacular event - the Beijing Olympics. Flickr has posted and explained before (Yahoo) and after (OSM) maps. The difference is immediate and self evident.

Inevitably, it was only a matter of time before the GNU/Linux community got its mitts on OSM and started to look at ways of integrating it into KDE. Yes, of course, Google Earth and Google Maps are available and they are pretty good but if, like the Free software Foundation (FSF), you believe that it is not possible to draw computer users away from proprietary software if there are no free, non-DRM alternatives you'll be glad to hear that Marble, a Virtual Globe and World Atlas is an alternative.

Although Marble is out of the KDE education stable, it has the potential to be a match made in Heaven once OSM is in the frame. The latest version of Marble, 0.6, is bundled with KDE 4.1 and whilst it cannot match Google Earth at present it has plenty of potential - and integrating OSM is definitely a step in the right direction. Support has been added for OSM and it has the ability to read KML files (keyhole markup files) and street level views can be updated online so as cartographic data accumulates the detail improves. Whereas Google maps' terms of use only permit viewing from within the confines of a browser OSM can be viewed from any application, including Marble. There has even been talk of incorporating OSM into Koffice. What would be particularly useful in the Marble search function however would be that ability to search by post code (zip codes if you are in the USA). It would also be useful to integrate OSM into a free software calendar application with the ability to attach a map related to upcoming events with the ability to embed in an e-mail. That should be possible through Kparts, or DCOP (replaced by D-Bus in KDE4).

The founder of OSM realises the importance of this - and so do the Ordnance Survey. They are the guardians of post codes in the UK and know the commercial value of "owning" it. Freeing the post code is a way to submit a longtitude and latitude collected via GPS cross referenced to a postcode. There is a very obvious connection with what OSM is doing which is why it includes details on its website. A postcode map has been already been created which superimposes postal areas over OSM maps. So, if you are surveying an area with GPS for OSM you can gather postcode data too which can be uploaded to freethepostcode.

Finally, OSM's profile outside the free software community has been recognised. Multimap will start funding OSM, an OSM-plugin has been developed for Cadcorp and Nestoria are using OSM for their property maps - for good measure Nestoria supported the development of Mapstraction, a free and open cross-mapping javascript library used in Geopress.

OpenStreetMaps is a classic instance of scratching an itch and instead of bleating about proprietary software going out (literally) and doing something yourself. It is always so easy to ask why someone doesn't do something until you realise that you are that someone. Any participation in any free software project is demanding of time and often requires a high level of technical and programming skills, but the beauty of OSM is that anyone can participate and contribute. It's not everyday that you get the chance to help map the world. Mark Twain said "buy land, they're not making it anymore". True, but you can at least map what's there.

Copyright information: This entry is (C) Copyright by its author, 2004-2008. Unless a different license is specified in the entry's body, the following license applies: "Verbatim copying and distribution of this entire article is permitted in any medium without royalty provided this notice is preserved and appropriate attribution information (author, original site, original URL) is included".

Published Tuesday, October 21st, 2008

Written by Gary Richmond

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