FAQ

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For License change, see Open Data License FAQ.
For Modelling questions, see Map Features.
For Legal aspects, see Legal FAQ.
For Developers, see Developer FAQ.
For Wiki, see Wiki 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.

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. Sometimes data itself powering this services is not available at all, or blocked by unfriendly licensing or extreme fees.

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 is 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, citizen scientists, social activists, cartographers and the like to fulfill their plans without being limited either by Google's API or by their Google Maps/Google Earth Additional Terms of Service: 

 When using Google Maps/Google Earth, you may not […] use Google Maps/Google Earth to create or augment any other mapping-related dataset (including a mapping or navigation dataset, business listings database, mailing list or telemarketing list)
 
 (c) No Creating Content From Google Maps Content. Customer will not create content based on Google Maps Content. For example, Customer will not: (i) trace or digitize roadways, building outlines, utility posts, or electrical lines from the Maps JavaScript API Satellite base map type; (ii) create 3D building models from 45° Imagery from Maps JavaScript API; (iii) build terrain models based on elevation values from the Elevation API; (iv) use latitude/longitude values from the Places API as an input for point-in-polygon analysis; (v) construct an index of tree locations within a city from Street View imagery; or (vi) convert text-based driving times into synthesized speech results.[1]

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. This is similar to how you can use an open source media player to play copyrighted songs: the copyright of the software doesn't change the copyright of the data that it uses.

(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:

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 do not carry a guarantee of accuracy, either.

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.

In OpenStreetMap it is normal that one town is mapped in extreme detail, another has mapped road and bicycle infrastructure and nothing else while another is not mapped at all (for now!).

Who owns OpenStreetMap?

All of us do. The data and software are owned by you, me and many others, 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?

Anyone can help by improving map data!

Common Editors are the iD editor on osm.org and JOSM.

Go Map!! Is an easy to use iOS/iPadOS/macOS editor for OSM with support for adding POIs, editing nodes and ways, offline support, undo-redo, copy-paste tags, make ways straight, circular or rectangular and more.

StreetComplete is an Android app that is usable by people with no experience or knowledge about OpenStreetMap editing.

More ways to help are listed on the Getting Involved page.

How do you communicate?

Main article: Contact channels

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.

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

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 Mapbox.

See also page about imports.

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 "standard" map appearing on OpenStreetMap.org tends to be updated after a couple of minutes, but can also be longer depending on server load. 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 not at another, they will be visible after a while. Depending on your browser, you can try to 'force reload/refresh' the content. Check your software for the key combination (Ctrl+F5 and⇧ Shift+Ctrl+R are common). See more at Browser cache.

Note that very low zoom levels are updated much less often.

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:

  • Run JOSM validator or, if edit is old, check area on Osmose. Or use other QA tool
  • all your ways are tagged with something appropriate that will be rendered (e.g. highway=tertiary). However, do not tag an object with unsuitable tags just to get it shown on a specific map.
  • your tags are in lower case: highway instead of HIGHWAY or Highway.
  • you use an underscore “_” instead of a space in tags such as highway=bus_stop

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.

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.

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 is the most popular worldwide and have the largest coverage. But for many areas there is more local superior one. 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.

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,

  • On one of the map layers on OpenStreetMap.org, zoom in and click the