Vi:FAQ
Những câu hỏi thường gặp
Tại sao là OpenStreetMap?
Tại sao bạn dùng OpenStreetMap?
Dữ liệu địa lý (geo data) không miễn phí ở nhiều nơi trên thế giới, chẳng hạn như Vương quốc Anh. Ở những nơi này, thường có những cơ quan có trách nhiệm đo đạc và thành lập bản đồ riêng. Nếu bạn muốn sử dụng dữ liệu, bạn sẽ phải liên hệ với họ và mất một khoản phí để có thể dùng được. Tất nhiên, khoản phí này không hề nhỏ một chút nào - nhất là khi bạn muốn mua dữ liệu số. Ngoài ra, để bảo vệ bản quyền, những cơ quan này còn có thể sửa đổi một chút tính chất của dữ liệu ( về hình học cũng như thông tin của đối tượng) so với thực tế. Nếu bạn sử dụng dữ liệu của họ mà không được phép, những sửa đổi đó có thể là một bằng chứng về việc vi phạm bản quyền của bạn. Dữ liệu này cũng có thể đã quá cũ và không còn chính xác nữa, điều này sẽ gây khá nhiều khó khăn khi bạn sử dụng lại chúng.
Data from commercial mapping agencies contains lies, or Copyright 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. Khi công nghệ ngày càng tiến bộ và phát triển, việc trang bị cho mình một chiếc GPS nhỏ với giá thành phù hợp cũng đồng nghĩa với việc bạn có thể tự làm cho mình một bản đồ để sử dụng theo ý muốn.
Tại sao bạn không chỉ sử dụng Google Maps cho dữ liệu của mình?
Vì dữ liệu được bảo vệ bản quyền và sở hữu bởi một ai đó như Ordnance Survey hay TeleAtlas. Google cũng chỉ mua bản quyền sử dụng lại dữ liệu đó. Nếu muốn sử dụng, bạn cũng sẽ phải trả phí cho việc đó 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 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 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 set of links to copyright legislation.
Một dự án như OSM có thể làm ra những bản đồ có độ chính xác như thế nào?
OSM cũng giống như Wiki, không có một đảm bản nào về tính chính xác của dữ liệu. Vì bản chất của Wiki là dữ liệu được đóng góp bởi nhiều người và đảm bảo sao cho luôn có 1 kết quả chính xác nhất cho tất cả. Nếu một ai đó cung cấp dữ liệu sai, không chính xác thì số người tham gia còn lại có thể kiểm tra và sửa đổi cũng như loại bỏ những sai sót trên.
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.
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?
We have a lot of very keen contributors!
We are also bringing in TIGER data for the US, and we have AND Data for the Netherlands (kindly donated), GeoBase data from the Canadian government, and we are always on the look out for other Potential Datasources. However, all of our data must come from public domain or open licensed sources which are compatible with our OpenStreetMap License. Even in those areas where free data exists, there is generally a lot of room for improvement via our wiki-like community map editing process.
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 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.
Giấy phép của OSM cho phép làm gì với dữ liệu OSM?
Xem chi tiết tại trang hỏi đáp về pháp luật và giấy phép.
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?
The OpenStreetMap community is large, and spread across many locations, speaking different languages, and focussing on different interest areas. So the answer is we don't always communicate very well! But we do our best.
We have various Contact channels.
- We have many mailing lists. The talk list is very high traffic. This is where most discussions take place and decisions are made. There is also lists for dev and newbies and over twenty other lists. See mailing lists.
- The forum at forum.openstreetmap.org is a good place to get help.
- For live chat, our main IRC channel is irc://irc.oftc.net#osm . There's a couple of others. SeeContact#IRC
- Some announcements and interesting developments are made on the blog at http://www.opengeodata.org/ .
- And there's this wiki. It's used more for reference than for discussions, but the tags we use for the map (Map Features) are organised through the wiki.
See Contact for more information
Tôi có thể đóng góp bằng cách mua một thứ gì đó được không?
Ồ, tất nhiên là quá được rồi. Bạn hãy xem thêm tại đây nhé
Is there any ongoing scholar research on OpenStreetMap?
Numerous universities and schools worldwide are using OSM within the scope of research. See Scholar Research for more information.
Biên tập
Tôi có dữ liệu GPS, tôi có thể làm như thế nào để đóng góp cho OSM?
Bạn có thể tải dữ liệu GPS của bạn lên OSM, như vậy bạn và người khác có thể dùng chúng để vẽ lại bản đồ. Bạn sẽ cần phải đăng kí một tài khoản tại OSM trước khi làm việc này. Xin xem thêm tại trang lưu các tracks mà người khác vừa tải lên Khi đã tải dữ liệu GPS lên OSM xong, bạn có thể sử dụng những thông tin từ dữ liệu GPS của bạn để vẽ lại các tuyến phố, con đường và các đối tượng khác cho OSM. Bạn có thể làm điều này bằng cách:
- biên tập dữ liệu trực tuyến, sử dụng Potlatch - một chương trình viết bằng Flash dễ sử dụng, chạy trên trình duyệt Internet; hoặc
- sử dụng JOSM - công cụ có nhiều chức năng cho phép bạn biên tập dữ liệu GPS trên máy tính của mình trước khi tải chúng lên OSM
- nếu bạn không có GPS thì bạn vẫn có thể tham gia đóng góp cho OSM, xem thêm tại đây.
Tôi có dữ liệu mở (không phải GPS), vậy tôi có thể tải nó lên OSM bằng cách nào?
Nếu bạn có dữ liệu mở (public domain), bạn có thể thêm nó vào cơ sở dữ liệu của chúng tôi nhưng hãy chắc chắn đó là dữ liệu mở. Nếu bạn không chắc chắn về vấn đề bản quyền, hoặc đó là một lượng dữ liệu lớn, hãy thảo luận trước đã (liên hệ). Chúng tôi sẽ rất quan tâm đến vấn đề của bạn. Bạn cũng có thêm vào danh sách nguồn dữ liệu tiềm năng và mô tả nó. Về việc tải một lượng lớn dữ liệu lên OSM, bạn có thể sử dụng trực tiếp APIcủa OSM. Hoặc bạn cũng có thể chuyển đổi dữ liệu của bạn sang định dạng OSM và dùng JOSM để xem, biên tập và tải lên OSM
What images and maps may I use to make maps from?
Most maps have copyright restrictions. This includes images from "free beer" sites as Google Maps, and printed paper maps, even if you scanned them yourself. 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 there are some Potential Datasources, in particular we have imported TIGER data for the US, AND Data for the Netherlands. We also make use of out-of-copyright maps although they are very old, and Yahoo! Aerial Imagery (which we have special permission to trace over).
I uploaded my GPS track. Now it says "PENDING" and the queue's eight hours long. What gives?
At busy times, especially weekends, there can indeed be a wait before your track is added to the database. But you don't need to wait for this to start mapping.
If you're using Potlatch, find the 'edit' link to the right of your track (in the GPS traces listing), and click this - not the usual Edit tab at the top.
If you're using JOSM or another offline editor, just load the track from your hard drive.
Tôi vừa thay đổi bản đồ. Làm sao xem được các thay đổi của tôi?
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 around one hour. When you try to view the map for that area, it will flag the area to the rendering software. Please keep in mind that "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.
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:
What shall I do for roads that have multiple values for a tag?
If the values belong to more than one way, in most cases the best solution is to use several Relations! See E-road_network for some good examples!
If the values only belong to one way, separate multiple values for the same key with semicolons; for example, nat_ref="B500;B550" for a road that is designated both B500 and B550. While you may see other characters being used as delimiters (for example, "/" (solidus), " " (space), "-" (hyphen), or "#" (number sign)), the semicolon is the only accepted character.
If a semi-colon exists in the actual value of the data, enter it as two consecutive semicolons.
What makes a road belong to a city?
This is often asked by beginners. There should be a closed way marking the extent of the city with a place and a place_name tag, as well as a single node with a name and place to mark where to draw the city-name. See Key:place for details. In the actual map such a shape does not exist for many cities, thus only the distance to the central node that marks the city can be used in these cases. For exceptional cases an is_in/is_in:city can be used.
Another user has changed something I drew. I think they're wrong. How do I contact them?
To find the name of the user who last edited an object,
- In Potlatch (the Edit tab on the web site), select the way and press H for history.
- In JOSM, click the way look in the Author's panel (use the button in the bar down the left side or CTRL-A to make this visible if not already)
- 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. For Potlatch just click the 'Mail' button in the window that appears when you press H. Otherwise, for a user called (say) Fred28, go to https://www.openstreetmap.org/user/Fred28 and click "Send message" to send them a message. (This will not work in the rare case of anonymous edits)
You can use Potlatch's revert and undelete functions to restore the previous version of a way.
Incidentally just moving the position of a way means the node positions are changed: the way itself is unchanged.
Editing with Potlatch
See the separate Potlatch/FAQs page.
(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
I tried to download my town/city/region - why doesn't it work?
Chances are the area you tried to download is too large, and the server probably timed out before getting the data to you. Try on a very small area first to make sure its working OK. If thats ok, then you are best to download the town in smaller segments. Presently, you cannot download an area larger than 0.3 degrees in either dimension.
If you really want large areas of data, the best approach would be to download the planet.osm file, which is generated weekly. This file is basically a snapshot of the OSM database and contains all valid data.
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.
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 and forum. You need to register on the www registration page to actually be able to work with OSM data.
Using a GPS
Why didn't my GPX file upload properly?
Your GPX should consist of trackpoints with valid timestamps. The ele(vation) tag is optional and will default to 0. Note if using a Garmin GPS device: Many of these units have the facility to save the track that strips out the timestamps. Saved tracks will fail to be imported to OSM because of this. Instead make sure you upload GPX files created from the active track(s) from the device rather than any tracks you have saved.
The format for the gpx files as 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>
GPX 1.1 will also work:
<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<gpx version="1.1"
creator="EMTAC BTGPS Trine II DataLog Dump 1.0 - http://www.ayeltd.biz"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://www.topografix.com/GPX/1/1"
xsi:schemaLocation="http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd">
<metadata>
<name>GPS Receiver track log</name>
<desc>Tallinn (car)</desc>
<author>
<name>Michael Collinson</name>
<email id="mikes" domain="ayeltd.biz" />
<link href="http://www.ayeltd.biz"><text>AYE Ltd.</text></link>
</author>
<time>2007-10-02T09:22:06Z</time>
<keywords>Estonia, Tallinn, A. Weizbergi</keywords>
<bounds minlat="59.4367664166667" maxlat="59.4440920666666" minlon="24.74394385" maxlon="24.7971432"/>
</metadata>
<trk>
<src>Logged by Michael Collinson using EMTAC BTGPS Trine II</src>
<link href="http://www.ayeltd.biz"><text>AYE Ltd.</text></link>
<trkseg>
<trkpt lat="59.4408327" lon="24.74516185">
<ele>44</ele>
<time>2007-10-02T07:54:30Z</time>
<fix>3d</fix>
<hdop>300</hdop><vdop>300</vdop><pdop>300</pdop>
</trkpt>
</trkseg>
</trk>
</gpx>
There are two things the importer won't do. First, it won't take in GPS points without timestamps as they're to be used to work out speed and so on. The other is that it doesn't import waypoints and your file consists only of waypoints.
The reason for this is that if you reset many GPS units or download map data to them, then you often get copyrighted data put in the GPX. The most famous example is that if you reset a Garmin GPS unit then it will put the locations of the Garmin offices around the world as waypoints on the unit.
Tracks will fail to upload if data formats are not correct, for example my GPS setup occasionally throws in a NaN as an elevation value. Deleting those lines from the file fixes the upload.
Another reason for import failure may be on the server-side. Please consult the platform status page to see whether a technical problem is known that prevents even correct gpx files from being imported.
Why are the points on my tracks spaced out?
This is due to the GPS device (usually a Garmin) being set to record on 'Auto', which saves space by recording fewer points on straights. It's not usually a problem in rural areas, but isn't much use for city mapping. To make the gps record more points, go to the track settings menu on your GPS, and change the recording method to either 'Time', or 'Distance'.
Time: Time will record points every 'x' seconds/minutes/hours. This can be changed on some gps devices. Having this setting will use up the memory fast, but will increase the points considerably. The disadvantage of this method of saving is that when moving slowly with the GPS device the points will become densely packed. For example, many Garmin GPS's have a maximum tracklog capacity of 10,000 points. (Note that some devices also allow a log to be stored on a memory card in addition to the regular tracklog.) Setting a time interval of 1 second normally gives close to 3 hours of mapping (always a few points are not written due to errors and satellite availability). For fast road driving a 1 second interval gives very good trace information. The 1 second interval also works well for cycling in urban areas. For walking the rate can be decreased without loss of track definition to 2 or 3 seconds. The interval can also be increased when the mapping time needs to be extended but try to avoid unnecessary time intervals. You can change the time interval on the fly, useful if you decide to stay out longer than planned. If your GPS-Unit doesn't impose you serious restrictions on storage capability experienced mappers generally use a setting of 1Point/s to get best results in all mapping conditions.
Some advantages of the time setting are that relative speed can be judged by the spacing, There are more points when you slow down for curves or turns and less on straightaways where you need fewer points.
Distance: Distance will record points every 'x' Meters/yards. This can be changed on some gps devices. Having this setting will use up the memory fast, although relative to your speed. The disadvantage of this method of saving is that when travelling on straight roads fast, (motorways/highways), unnecessary points will be recorded. Also if you are to be tracking a small area, if the 'x' value is too high, your route will be unclear. In general distance recording can miss the subtleties of curves and direction changes, especially in urban areas.
Wrapping: If the option is available to turn on, or off the wrapping function, then having it off is also advised. Having wrapping on means that when full, the gps device will make room to record the latest section of your route, by deleting the beginning of your route. It will delete the beginning, point by point, at the same rate as new points are created. The exception would be when you are logging track data to a data card in some Garmin models. The beginning data will be deleted from the device's built in memory, but not from the data card.
Why do I get bad signal / traces in city centers / near big metal buildings?
For a GPS to work and achieve some accuracy it needs to receive at least three satellite signals. Often when in city centers there are many tall buildings that can block these signals and stop the GPS from being able to work out where it is. There may also be multi-path effects from the material making up the buildings around you, whereby signals bounce off them so the receiver actually thinks it is somewhere in the buildings around. Another factor that can affect this is the number and position of satellites that can be seen at the time of logging; trying the route on another day or a different time of day may give better results.
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 satnav.
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.
Using OSM maps and data
How do I link to a particular postcode on OSM from my own website?
You can link to the search page for a particular postcode:
https://www.openstreetmap.org/geocoder/search?next_controller=site&next_action=index&query[postcode]=AA1%201AA
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/index.html?mlat=[latitude in degrees with decimals]&mlon=[longitude in degrees with decimals]&zoom=[zoom level 1-17]
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?
The easiest way is to use static data, i.e. to export data (using the 'Export' tab) and put it onto your website.
For dynamic display there is a Google Maps-like Javascript API; see the Export page on this wiki.
Can I download a vector map?
Use the 'Export' tab to download in SVG or PDF format. If you need other formats, see the Export page on this wiki.
Why doesn't 'Export' work?
On Wednesdays, the rendering database is reloaded from the main map database. This means the rendering database (used by Mapnik) is temporarily unavailable for the Export feature.
You can export an Osmarender/Tiles@home image instead, or wait until the database has finished reloading.
We aim to fix this in the medium term.
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.
Developer questions
Why should I not begin development on a new editor, one better/different/prettier than current editors?
There are already several very useful OSM editors in development, and confusing the space with "yet another" platform will only duplicate effort. Please consider contributing to one of the editor development efforts already in progress, such as JOSM, Merkaartor, or Potlatch.
Why don't we spread the load on the OpenStreetMap database across a number of servers?
Sharing the OSM server load via MySQL replication, or BitTorrent, or carrier pigeon is often recommended, but the idea has so far gained little momentum -- in terms of real development effort. If you have the system administration or coding expertise to implement such a distributed system, please do not hesitate to volunteer on the mailing list.
As a starting point, you may want to familiarise yourself with the existing software infrastructure, as described in the Development pages.
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 OpenStreetMap 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.
Can I write a script or bot to automatically edit OSM data?
If you wish to script changes to the OSM database then you can do so using the API. However, as such scripts can be very damaging if not done correctly, please read the Automated Edits page and the associated Code of Conduct for some good advice before you start.
Questions from GIS people
What geographic datums are used in OpenStreetMap?
OpenStreetMap uses the WGS-84 lat/lon datum exclusively. All uploaded tracks and edits should always be in WGS-84, the default datum for GPS receivers.
What is the map scale for a particular zoom level of the map?
The following table shows the nominal scales for each zoom level. Data from http://labs.metacarta.com/osm/
So, for example the nearest equivalent to an OS Landranger map at 1:50,000 is zoom level 13 (nominally 1:54,000).
Note: figures are rounded to millions from levels 8 to 2.
| Table of Levels/Scales | ||
|---|---|---|
| Zoom level | Scale as representative fraction | Meters per pixel |
| 18 | 1 : 1,693 | 0.597164 |
| 17 | 1 : 3,385 | 1.194329 |
| 16 | 1 : 6,771 | 2.388657 |
| 15 | 1 : 14,000 | 4.777314 |
| 14 | 1 : 27,000 | 9.554629 |
| 13 | 1 : 54,000 | 19.109257 |
| 12 | 1 : 108,000 | 38.218514 |
| 11 | 1 : 217,000 | 76.437028 |
| 10 | 1 : 433,000 | 152.874057 |
| 9 | 1 : 867,000 | 305.748113 |
| 8 | 1 : 2 million | 611.496226 |
| 7 | 1 : 3 million | 1222.992453 |
| 6 | 1 : 7 million | 2445.984905 |
| 5 | 1 : 14 million | 4891.969810 |
| 4 | 1 : 28 million | 9783.939621 |
| 3 | 1 : 55 million | 19567.879241 |
| 2 | 1 : 111 million | 39135.758482 |
See also http://almien.co.uk/OSM/Tools/Scale/
Note that actual scale varies with cos(latitude)
Why aren't you using Open Geospatial Consortium (OGC) schemas and software for OpenStreetMap?
There are many existing tools which people often recommend for OpenStreetMap to use. The problem is, most of them are hard to use and maintain for a variety of reasons, and people are very reluctant to volunteer to help set them up and run them. 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.
It's not that OpenStreetMap as a community is against OGC standards, but OpenStreetMap has been built iteratively using the simplest approach that could possibly generate useful maps. The focus is on street data and maintaining a 'wiki' approach to editing where all changes are logged and can be rolled back. Off the shelf tools don't support that in the way we'd like.
Help is needed on choosing which OGC tools and standards to use, and integrating them effectively into our existing systems. Please get in touch if you can spare the time and expertise to do this.
Also, see Why not GPX for a similar discussion about why GPX was rejected as a transport format.
I have geo-referenced photography/shapefiles/waypoints for my area, how can I upload them?
We'd love your high resolution geo-referenced aerial photography/satellite images if they are free of copyright restrictions for derived works, or you are the copyright holder and can grant us the relevant rights - get in touch via the mailing list. You can also contribute your imagery to OpenAerialMap, which is available as a background layer in Potlatch, Merkaartor and JOSM.
For shapefiles and other data formats, again, get in touch via the mailing list.
What Geotagging do you use?
See Geotagging.
Admin
How can I close my account?
Contact a sysadmin, the sysadmin 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 sysadmin needs to contact you in the future.
If you have made any modifications or additions to OpenStreetMap, the sysadmin will ask you to license these under any future OpenStreetMap Licenses or to release as public domain.
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:
- 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.
- 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.
- 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.