FAQ

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For License change, see Open Data License FAQ.
For Modelling questions, see Tagging FAQ.
For Legal aspects, see Legal FAQ.
For Developers, see Developer FAQ.

In addition to this FAQ, there is a collaboratively edited question and answer site where you can read more questions about OpenStreetMap and ask your own. Feel free to contact the community as well.


Contents

Is it OpenStreetMap or Open Street Maps?

OpenStreetMap is the correct spelling. One word, three capital letters, one map. OpenStreetMap is also a Trademark.

Why OpenStreetMap?

Why are you making OpenStreetMap?

Geographical data (geo data) is not free in many parts of the world. 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. 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. In the USA crude data (such as TIGER) is in the public domain, however refined data and finished maps are generally commercially copyrighted.

Data from commercial maps sometimes contain lies, or Copyright Easter Eggs, to catch 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 multiple organisations like the Ordnance Survey. Google/whoever just licenses it. If we were to use it, we'd have to pay for it.

Long answer:

Most hackers around the world are familiar with the difference between "free" as in "free beer" and as in "free 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, fine. That's not true of every project, though. We need a free dataset which will enable programmers, social activists, cartographers and the like to fulfill their plans without being limited either by Google's API or by their Terms of Service. The data used in Google Maps is either owned by Google itself, or sourced from NAVTEQ and Tele Atlas, 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 significant financial investments to gather 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:
    • "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 Maps 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".
  • Can I use Google Streetview ? on help.openstreetmap.org

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. Then again, few proprietary maps carry a guarantee of accuracy, either. In fact, some have artificially-introduced errors.

The essence of a wiki-style process is that all users have a stake in having accurate data. If one person puts in inaccurate data, maliciously or accidentally, the other 99.9% of people can check it, fix it, or get rid of it. The vast majority of good-intentioned participants can automatically correct for the few bad apples.

As they say, though, 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.

A full editing history is stored for each user. Since April 21, 2009, users can attach Wikipedia-like edit summaries to their edits, and there is a History tab on the main page that shows recent edits to the selected area.

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 corresponds to your own knowledge. Maybe you will see something wrong or inaccurate. More likely you will find there's nothing there yet. At this stage, our main challenge is to extend our coverage, without copying from existing maps. As on Wikipedia, it's easy to edit, so you can help!

You seem to have a lot of existing map data. Where did it come from?

Many keen contributors, and sporadic imports of data from open-licensed sources. In areas where there are no such data sources (most areas) we have to start from a blank slate, and head out there to survey the streets ourselves. Despite starting from scratch, we have achieved a good level of completion in many places.

Why is the data sometimes inconsistent?

"OpenStreetMap is a free editable map of the whole world. It is made by people like you." Which means the database will always be subject to the whims, experimentation, and mistakes of the community; this is precisely OSM's strength since, among other things, it allows our data to quickly accommodate changes in the physical world.

Who owns OpenStreetMap?

You do. The data and software is owned by you, the contributors.

There is an organisation called the OpenStreetMap Foundation which exists to protect, promote, and support the project, but does not own the data.

What does your license allow me to do with the OSM Data ?

See Legal FAQ and License for more information.

How do I help?

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.

How do you communicate?

Main article: Contact

The OpenStreetMap community is large, spread across many locations, speak different languages, and focus on different areas of interest. So the answer is we don't always communicate very well! But we do our best.

Can I show my support by purchasing cool stuff?

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

Is there any ongoing scholarly research on OpenStreetMap?

Numerous universities worldwide are studying various aspects of OpenStreetMap or are using OSM data in their research. See Research for more information.

Editing

Do I need to own a GPS device to contribute to the map?

No. When OpenStreetMap first launched the map started as a blank canvas. GPS devices were therefore useful to determine the position of roads and other map features. Today we have numerous data sources that can be used to determine an accurate position, including aerial imagery from bing, and of course the existing OpenStreetMap data.

You can still upload your GPS track logs (also called traces) to OpenStreetMap, so that you and others can trace over them to draw maps. This is particularly useful for rural and mountainous areas where aerial imagery may be of low quality, or inaccurately aligned. You'll need to be a registered OSM user to do this. See upload for guidance and traces for a list of publicly available GPS traces.

What GPS should I buy? Can I use a "satnav" in-car unit?

See GPS reviews. Some in-car units will generate the tracklogs that OSM use, but you must make sure you turn off the "Snap to Road" option - otherwise your tracklog will be linked to the copyrighted map in your satellite navigation system.

I have public domain non-GPS data, how can I upload it?

If you have public domain data obtained from non-GPS sources (for example, a municipality's public information website), it may be suitable for importing. If you want to import then see the Import Guidelines. Importing can be a highly technical process and both technical experience and extensive OSM experience are required to complete an import successfully. The challenge with imports are not primarily technical, but a community challenges. You need to talk to local mappers and check that they are happy with the import as well as the wider community.

Your best option may be making the data available to the community and if someone is interested they can proceed with the import process.

What images and maps may I use to make maps from?

Most maps have copyright restrictions. This includes any data from "free beer" sites as Google Maps and Wikipedia and printed paper maps, even if you scanned them yourself. Most Commercial aerial/satellite photography is also copyrighted.

You should not use copyrighted maps in any way while editing OpenStreetMap (unless it is compatible with our license). "Using" includes tracing over the map, copying a name from the map, or pinpointing a coordinate on the map. To be on the safe side, we tend to regard all of these as a form of copying, or "creating a derived work". Generally speaking, it's best not to even look at copyrighted maps while you are editing OpenStreetMap.

So what can you use? Not very much, which is why we are doing all this re-surveying from scratch. However OSM has permission to use some Datasources including imported TIGER data in the USA, AND Data in the Netherlands, and recent aerial imagery from Bing and Mapquest.

Why is the satellite imagery low resolution? Is there other satellite imagery that I can use that has more detail? Can you update it? How often is it updated?

The Aerial Imagery is from a variety of sources that we have permission to use - Bing and Mapquest are the most popular and have the largest coverage. The resolution and age of the imagery varies, and it is not updated on a regular basis. You may even notice the age and quality of imagery from same source may be different in your town. See Aerial Imagery for more details. OSM neither controls nor owns the satellite imagery so we cannot request updates.

I have just made some changes to the map. How do I get to see my changes?

Because map images take a little while to render, the map tiles are cached, and only updated on a periodic basis, rather than immediately after you edit it.

The default map (the Mapnik layer) tends to be updated after a couple of minutes. When you try to view the map for that area, it will flag the area to the rendering software. Please keep in mind that the browser will cache the map and "tiles" at particular zoom levels are not updated all at once. Therefore during the update period you may see your changes at some zoom level, while at another, they will be visible after a while.

See also Question:I have made edits but they don't show up on the map and Question:How often does the main (mapnik) map get updated for a more thorough explanation.

If your data is still not appearing and you are pretty sure that the one or the other renderer has done its job, then you might have a tagging problem. Check that:

  • all your ways are tagged with something appropriate that will be rendered (eg highway=tertiary)
  • your tags are in lower case: HIGHWAY and Highway will not work.
  • you have underscore '_' and not a space for tags such as highway=bus_stop

What shall I do for roads that have multiple values for a tag?

Where different tag values apply to different sections of a road, we always split the road up into several ways. Something you think of as a single road, does not need to be represented as a single way. Splitting a road up into many ways is normal mapping practice. e.g. for short sections where bridge=yes applies, or sections of road with different maxspeed=* values.

If you worry about how to represent the whole length of road, you might look at using relations to re-group ways. WikiProject Europe/E-road network gives some examples of this.

If you have multiple different values for the same key, applying to the same element, then you may need to use the semi-colon value separator. For example, nat_ref=B500;B550 for a section of road that is designated both B500 and B550.

Another user has changed something I edited. I think they're wrong. How do I contact them?

To find the name of the user who last edited an object,

  • In Potlatch, select the way and press H for history (screenshot) and then click the 'Mail' button to contact them.
  • In JOSM, Select the object and then either hit CTRL+H or enable the Author's panel by selecting the icon of a blue book on the left side bar or hitting ALT+Shift+H or hit Ctrl+Shift+H to open the history on www.osm.org.
  • In the Slippymap on the OSM home page, use the + button on the map and check the checkbox on Data. Then, the data panel will be show on the left side of the map. Click Load data and wait until the features on the current data are shown on the map. Click the feature of which you want to know the history. It shows all the properties of the feature on the data panel and a link 'Show history' at the bottom of the data panel. Click the Show history. Finally, you can get the user name of the person who last changed that way. Farther, by clicking the Detail link on the history tab, you can get links to the user pages of all the authors.

You can then go to their user page. Otherwise, for a user called (say) Fred28, go to openstreetmap.org/user/Fred28 and click "Send message" to send them a message. (This will not work in the rare case of anonymous edits)

Incidentally just moving the position of a way means the node positions are changed: the way itself is unchanged.

For more information see this. Also see revert.

How do I track edits of a region?

See the list of various tools at Quality assurance#Monitoring Tools.

Editing with Potlatch

Main article: Potlatch/FAQs

Potlatch is the map editor that you get when you click the "Edit" tab on the main site. If you don't know which editor you're using, it's probably Potlatch!

Editing with JOSM

See also the Josm Guide.

I tried to download my town/city/region - why doesn't it work?

Chances are the area you tried to select is too large and the server probably timed out before getting the data to you. In order to conserve OSM's bandwidth, you cannot download or select to edit an area larger than 0.3 degrees in either dimension through the web interface. For editing, it is recommended to work on smaller areas.

If you really want larger areas of data, the best approach would be to download planet.osm or an extract. These are snapshots of the OSM database for the entire planet or a specific area.

I want to create a very long way - how do I download OSM data for such a big area?

In order to be able to easily handle long roads, you should not make one long road out of it. You should rather split the road into several ways. As a rule of thumb, no way should be longer than 10-15 km. Typically, they will actually be much shorter.

Applications like route planners for example will be able to easily join the ways to one road again. This type of application will need to postprocess the OSM data anyway.

For motorways for example, it makes sense to make a way from one exit to the next. Also, intersections of motorways should be the point where you split a road into ways.

Using OSM maps and data

Main article: Using OpenStreetMap

How do I link to a particular latitude and longitude on OSM from my own website?

You can link to the slippy map with a specific latitude and longitude and zoom level:

https://www.openstreetmap.org/?mlat=[latitude in degrees with decimals]&mlon=[longitude in degrees with decimals]&zoom=[zoom level 1-19]

Coordinates must be positive for North and East, negative for South and West. For example, 28° 44' 16.09"S would be mlat=-28.737803 and 24° 45' 49.33"E would be mlon=24.763703 (that's Kimberley, South Africa, in case you're wondering).

Zoom levels: 1 = full zoom out, 17 = full zoom in.

Or link to a static image

How can I display maps on my website?

Read Getting Started With Leaflet on switch2osm.org

How can I download a map?

Use the 'Export' tab to download in SVG or PDF format. If you need other formats, see the Export page on this wiki.

How can I extract information [e.g. POI's] from OpenStreetMap (like a list and location of all of the Churches in a certain area)?

  • If you want a large batch of POIs, download planet.osm or an extract and then use software that processes OSM data (e.g. osmosis) to extract your desired information.
  • Or use the API. See getting poi data from OSM for a more detailed explanation.

How can I download this data and put it in my GPS?

If you have a Garmin unit, see OSM Map On Garmin. Several users provide ready-made Garmin format maps for you to download and copy to your GPS.

Why doesn't 'Export' work?

When the rendering servers have a high load from traffic to the main map some of the exports gets temporarily disabled. This is because the rendering of custom images from the export tab takes a lot of resources compared to the slippy map.

If you want to use the exports you can try again later or see other alternatives.

Where can I find software using OSM data?

For current software using OSM, see the Software page or its category, and also neat stuff for more experimental ideas.

For a more development-related angle, see Routing (and its category), the Beginners Guide topic on usage, and the Developers' pages.

Questions from GIS people

What geographic datums are used in OpenStreetMap?

OpenStreetMap uses the WGS 84 lat/lon data exclusively. All uploaded tracks and edits should always be in WGS 84, the default data for GPS receivers.

What is the map scale for a particular zoom level of the map?

Main article: Slippy_map_tilenames#Resolution_and_Scale

Why aren't you using Open Geospatial Consortium (OGC) schemas and software for OpenStreetMap?

We choose technology for openstreetmap.org based on speed & flexibility. Some OGC standards and implementations fit this bill, but others do not. We used to use MapServer for serving static versions of our maps, but unfortunately we found it to be unthreaded, slow, and hard to extend - we replaced it with Mapnik. If you'd like to develop integration with OGC tools, let us know.

See Why not GPX? for a similar discussion about why GPX was rejected as a transport format.

What Geotagging do you use?

Main article: Geotagging

Admin

Why doesn't my login work?

There are two different logins for the OSM project: one is for this wiki only, and the other is for the website, API, forum and the help site. You need to register on the website to edit OSM data.

How can I close my account?

Send an email to the support address and an administrator will disable your account and remove your details from the OpenStreetMap database. Your email address will usually be retained in the event that an OpenStreetMap administrator needs to contact you in the future.

Can I have more than one account?

Yes - see Creating_an_Account#Account_Names_and_Multi_Account_Policies.

Help - someone keeps deleting/reverting my edits. What do I do?

Please see the disputes page for details

I think someone's been entering copyrighted data - how do we deal with that?

If you find data that you suspect may have been copied from a copyrighted source or imported from a copyrighted source into OpenStreetMap without the owner's permission, please:

  1. Contact the user via using the 'send message' link from their user page (i.e. "www.openstreetmap.org/user/[user-name]") with the evidence. Be polite: it is important to remember that you might be wrong, they might have permission or it could be a simple misunderstanding. See Contact for more information.
  2. If there is no response (after 5 days) or you are deeply unconvinced by the response, email your evidence to the OSM Foundation so that the problem can be investigated.
  3. It may be that your report will be posted to the legal-talk mailing list (or a country specific list if this is more appropriate) for discussion - if so, you will be informed so you can join the discussion.

I am a copyright owner and my content is being used in OpenStreetMap Without Permission

  • If you are the copyright owner or represent the copyright owner, we can assist you directly by e-mail. You may contact us at data@osmfoundation.org with an informal request. Please cite the exact content in question. Correspondence is answered by a small team of volunteers.
  • This address is not for requesting permission to copy content from OpenStreetMap.
  • If you prefer to use or make a formal OCILLA request, you can send it to our designated agent. Digital Millenium Copyright Act Notice

I found a website using OSM that doesn't display the license

Our license says you have to display both the author and license (see Legal FAQ). If it's a major page, please read Lacking proper attribution.