FAQ

Frequently asked questions

About the project

Why are you making OpenStreetMap?

Geographical data (geo data) is not free in many parts of the world, including the United Kingdom. Generally these places have given the task of mapping to various government agencies who in return get to make money by selling the data back to you and me. The USA is the only major counter-example where due to copyright restrictions on the government, they have to give it away free.

If you live in one of these countries, then your taxes pay for the mapping and then you have to pay again to get a copy of it.

The data you get doesn't change much ove time, in general. Roads don't tend to get bored and move around. You can usually navigate in many areas with any post-war or more recent maps.

The data you get contains lies, or easter eggs, to catch out anyone copying it. These Easter eggs take the form of fake or missing streets, or features like churches and schools that don't in fact exist. If you make a map using their data, they can say "ah-ha! Gotcha!" from looking if you also copied these fake pieces of map. The map may also just be incorrect because for example you bought it a year ago and a path has been dug up in your local park since, or someone just made a mistake.

If you accept all of this then you still can't do anything with the data but photocopy it. In lots of places that's illegal too if you go beyond your fair use rights. You can't correct a street name, or add the pub/bar over the road, or use the data in a computer program without paying a lot of money. More money than you probably have. What about sending it to a friend, enclosing it in an invitation or posting it on a notice board? A lot of these are less legal than you might think.

Advances in technology like cheap GPS units mean you can now create your own maps, in collaboration with others and have none of the restrictions outlined above. The ability to do so allows you to regain a little bit of the community you live in - if you can't map it you can't describe it.

Why don't you just use Google Maps/whoever for your data?

Short answer:

Because that data is copyrighted and owned by people like the Ordnance Survey. Google/whoever just license it. If we used it, we'd have to pay for it.

Long answer:

Most hackers around the world are familiar with the difference between "free as in beer" and "free as in speech". Google Maps are free as in beer, not as in speech.

If your project's mapping needs can be served simply by using the Google Maps API, all to the good. But that's not true of every project. We need a free dataset which will enable programmers, social activists, cartographers and the like to fulfil their plans without being limited either by Google's API or by their Terms of Service.

At this point, the usual rejoinder is "Why don't you just get people to click a point on a Google map, then record the latitude and longitude in the Openstreetmap database? That's free, isn't it?"

Unfortunately not. The data used in Google Maps is sourced from Navteq and TeleAtlas, two big mapping companies. They, in turn, have obtained some of this data from national mapping agencies (such as the Ordnance Survey). Since they've made multi-million pound investments in gathering this data, these organisations are understandably protective of their copyright.

If you collect data from Google Maps in this way, you are creating a "derived work". Any such data retains the copyright conditions of the original. In practice, this means your data is subject to the licensing fees, and contractual restrictions, of these map providers. That's exactly what Openstreetmap is trying to avoid.

Please don't be misled by considerations of software copyright, or of Terms of Use. The Google Maps API can be incorporated into open source projects, sure. But this only governs how you use the software - it doesn't have any implications whatsoever for the data displayed by this API, which is still under copyright.

(It's not yet clear whether it's ok to create a derived work from aerial photography: some readings of UK law suggest that you can do this without 'inheriting' the copyright in the photography. A definitive ruling on this could open up new avenues for Openstreetmap and similar projects, but in the absence of such a ruling, we're continuing with the approach of sourcing our own, 100% independent data.)

Further reading:

• Google Maps' Terms of Service. Note particularly the 'Map Information' section, and that:
  • "Geocoding data for map content in Google Local is provided under license by Navteq... and/or Tele Atlas... and subject to copyright protection and other intellectual property rights owned by or licensed to NAVTEQ, TANA and/or such other third parties."
  • "Also, you may not use Google Local in a manner which gives you or any other person access to mass downloads or bulk feeds of numerical latitude and longitude coordinates."
• The Openstreetmap mailing list archives. You may want to search them for phrases like "derived works", and for a thread in October 2005 called "London locations".
• For UK users, here's a useful PDF of [www.patent.gov.uk/copy/legislation/legislation.pdf copyright legislation].

How can I get involved?

There are lots of ways to contribute to the Openstreetmap project. If you have a GPS unit you can use it to collect data and use our online tools to add the data to our collection. If you don't have a GPS unit you can still help. Ways to help are listed on the Getting Involved page.

Is there a mailing list?

Yes! See our Mailing Lists page.

Can I show my support by purchasing a cool poster of GPS trails in London?

Yes! See the Merchandise page for mouth-watering poster and wallpaper goodies.

How can a project like this create accurate maps?

By the very nature of the wiki-style process there is no guarantee of accuracy of any kind. And as they say, your mileage may vary. The Wikipedia project has shown that a large amount of good quality data can be collected but it can be difficult to weed out the inevitable errors.

Currently there are no processes or mechanisms, such as recent change lists and watchlists, that can be used to easily monitor edits within OpenStreetMap. I'm sure some mediating processes will be developed as soon as they become necessary.

At the moment the best way to answer this question is to judge for yourself. One way is to pick an area that you know well and use the OpenStreetMap viewer to see how well the map data (if there is any, it's still early days yet) corresponds to your own knowledge. Another method is to view OpenStreetMap superimposed on top of Google Maps: http://www.geoskating.com/gmap/osm-gmap.html, currently the content appears to be rather sparse but suprisingly accurate. Note: Don't use this link to help you contribute to OpenStreetMap, or even to correct errors, as that would infringe Google's copyright.

Editing and other technical questions

I have GPS data, how can I use it to help OpenStreetMap?

There are several ways to add your GPS data to the database. You can either:

• edit your data online, using the web interface, which runs as an applet within your browser; or
• edit at home using OSMeditor, which provides a way to edit GPS data locally on your computer into sensible tracks before uploading them to the server. JOSM is another tool for editing offline.
• and if you don't have a GPS you can still help, see Getting Involved.

I think I found a bug, what should I do?

If you find a problem with the map editing applet or the website, add it to the Openstreemap bug tracking database. We use trac, which uses your OSM username and password.

If you notice something incorrect/missing/wrong/unintelligible with the documentation you're reading right now, edit it! It's a wiki! For wiki advice and extensive documentation, see the mediawiki project, who created the software this wiki is running on.

I tried to register/upload but didn't get an email

OpenStreetMap and freethepostcode.org will email you things like account details and upon completion of uploading a gpx file. If you don't get an email, think did your spam filter get it? Did you let it through your whitelist?

My GPX file uploaded with less than the total number of points!

Your GPX should consist of trackpt's with valid timestamp. The ele(vation) tag is optional and will default to 0. Something like below is acceptable:

<?xml version="1.0"?>
<gpx
 version="1.0"
creator="GPSBabel - http://www.gpsbabel.org"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://www.topografix.com/GPX/1/0"
xsi:schemaLocation="http://www.topografix.com/GPX/1/0
http://www.topografix.com/GPX/1/0/gpx.xsd">
<time>2005-11-07T14:00:09Z</time>
<trk>
  <name>ACTIVE LOG</name>
<trkseg>
<trkpt lat="52.564001083" lon="-1.826841831">
  <ele>115.976196</ele>
<time>2005-11-07T12:03:31Z</time>
</trkpt>
</trkseg>
</trk>
</gpx>