Quality Assurance tools help lead to better quality of OSM data. Often, the tools achieve this by providing a list of bugs in the data, which mappers can then go and fix using editing tools. The bugs are either automatically detected based on rules and data analysis, or the tools provide a means of manually reporting them, or some combination of the two. There are many different ideas for how to do this, and what kind of bugs to focus on, hence many different tools.
OpenStreetMap is often more up-to-date and of a higher quality than other commercial maps when dealing with New and Changed Ways.
Bug reporting tools
These are tools that try to highlight and point out parts of the data that are likely wrong. There are also reports from manual quality checks by humans. In both cases, the reported issues may contain false positives and, when editing, care should be taken to ensure their accuracy. However, they can provide a very valuable visualisation of which areas need attention and can help spot and correct errors.
Notes is a feature of the OpenStreetMap website. Error reports can be added by using the 'Add a note' button in the lower right corner. Notes uses the same concept as OpenStreetBugs. It is anticipated that OpenStreetBugs will be phased out and superseded by Notes.
At OpenStreetBugs (OSB), you can mark and describe bugs on a map without authentication. These reports can be processed by map editors. Please use Notes instead in order to centralise the reports.
MapDust is a bug tool operated by skobbler, which is also integrated into their OSM-based turn-by-turn navigation solution, thus originally focusing on navigation-relevant bugs but now serving as a general bug tool. As many of its users (end users!) may not be aware of OpenStreetMap at all, there are also quite a few non-relevant error reports included, but it does contain many good reports that are not covered by other tools. If a bug is determined to be caused by OSM data, an OSM editor can fix the data and mark the bug as resolved. Currently it is available in English, German, French, Italian, Spanish and Romanian.
Error detection tools
Error Detecting Tools check the OSM data for potential data errors, inaccuracy or sparsely mapped places. Users should check if these structures are really wrong and correct the data for a continuously rising data quality.
- Keep Right↙
Keep Right (keepright.at) shows a large number of automatically detected potential errors on a map or in list form. It has a system for reporting false positives and for labelling a bug as fixed. It has rules to automatically detect the following error types: non-closed areas, dead-ended one-ways, almost junctions, deprecated tags, missing tags, bridges/tunnels without layer (careful - not always an error), motorways without ref, places of worship without religion, POIs without name, ways without nodes, floating islands, un-tagged railway crossings, wrongly-used railway crossing tag, objects with FIXME=* tags, and relations without type. Keep Right shows tens of thousands of errors, including many that have little impact (e.g. a stream intersecting a highway: technically a bridge is needed here, but existing renders assume the stream is in a culvert).
There is a documentation on how to solve keep-right-errors, currently only in German language: DE:Keep Right Users Guide
- France (the metropolitan area, including Corsica), and its overseas (all 5 DOM's, the smaller COM's, and New Caledonia);
- some nearby countries in Europe : Belgium, Luxembourg, and Switzerland;
- some nearby countries in Africa (50% of continent) and Indian Ocean;
- Two analyses are covering the planet in two cases:
- a cache of OpenStreetBugs errors
- administrative boundaries not close
- JOSM Validator↙
- The Gary68 tools↙
- WayCheck is a program which checks the OSM data (file) for open ends and crossings. The found positions must be evaluated by a user and he or she can correct the data in JOSM or Potlatch or post a mark in Openstreetbugs. The Waycheck page lists reports generated by the program and any user is encouraged to run reports and correct errors listed on the page and its links. This is especially useful for the quality of routing related data.
- MotorwayCheck lists problems related to highway=motorway. Page also shows reports.
- osmdiff is a program which compares two osm files and documents the changes in list and map form. Some reports can be seen here: osmdiff reports.
- unmappedplaces finds a list of potentially unmapped places. These are reported on the wiki page (or Unkartografiert page for German places) The query can be run for other countries as well.
- Mapping Quality is the successor of unmappedplaces. See the wiki page for the results. You get automatic street directory, KPIs (numbers) per place, maps that show status and CSV files for further processing.
- SomeChecks performs some checks: One-way check, Roundabout check, Double-node check (ways), Area Check.
- Relation Diff - Differences in relations
- Relation Check
- Coastline Error Checker↙
- OSM Inspector↙
- NoName Map↙
- TIGER Edited Map↙
- Coarse Highway↙
Ragged highways with few points (blog entry): Coarse Highways.
- OS Locator Musical Chairs↙
- Map of Turn Restrictions↙
Turn Restrictions Analyser↙
Maplint↙ Maplint is an osmarender configuration for highlighting errors. It used to be prominently available as a layer on the front page, updated by tiles@home.
Not updating anymore sletuffe 14:04, 30 October 2012 (UTC)
- US Interstate refs↙
US interstate refs List of ref numbers and corresponding OSM interstates.
FR:Servers/layers.openstreetmap.fr provides a slippy map with image layers to help people find possible errors in the data with worldwide coverage.
The service provides:
- layers with roads/street …
- having no name
- no ref
- no one-way
- drawing fixmes and notes texts.
- This tool also generates half-transparent coloured layers showing administrative areas by admin_level, as well as other "political" areas (used in France for mapping electoral subdivisions, as well as intercommunal structures of cooperation that do not fit the hierarchy of admin levels, but used as well in other countries for similar non hierarchical administrative, judiciary and electoral boundaries). These coloured layers allow searching easily for missing/broken/incomplete/unclosed boundaries as well as overlapping/duplicate boundaries of the same type, or boundaries that are not tagged correctly to be found by querying the OSM database with simple filters (for example missing tag "boundary=administrative", missing or incorrect value in "admin_level=*").
- layers with roads/street …
- Broken polygons↙
housenumbervalidator checks addr:* attributes for duplicate addresses, incomplete addresses, and possibly incorrect street names. Results are displayed on a slippy map. Currently validation is performed for Germany and Austria only, as there are some language-specific checks.
Other similar address tools:
- Maproulette aka Remap-a-Tron↙
Remap-a-Tron service, blog post and github – A customizable web application to crowd-source the fixing of specific mapping errors by randomly displaying an item of a specific type in potential need of fixing. Originally designed to highlight areas with ways deleted due to the license change, it is now expanding into a general front end for fixing identifiable problems. This service is also known as MapRoulette or maproulette.org.
- netzwolf's opening_hours & co. map↙
 - Check Opening_hours, Service_times...
- So that is what inaccessible road is!↙
So that is what inaccessible road is! - displays the road segments, which for various reasons are inaccessible (they are also called "not route-able parts of the road network") on a map and allows editing in JOSM or Potlatch.
- Routino error log↙
Routino a router for OSM data can generate an error log file (when run with the --errorlog option) that lists problems found that could be data errors or Routino's limited understanding of the data and which may affect the ability to calculate valid routes. Since the purpose of the Routino error log is to find data that causes problems for Routino it does not mean that all reported items are data errors.
- Bicycle tags map↙
Bicycle tags map is a web map that shows bicycle related tags. The goal of this web map with bicycle tags is rendering bicycle related tags that are not (properly) rendered on OSM’s 'Mapnik' map or on the cyclemap version. It can be handy for detecting errors in OSM.
- Administrative Grenzen in OSM↙
A map that compiles all the german boundaries within OSM and also visualizes errors (unclosed multipolygones) http://ags.misterboo.de
- Max Speed Overpass↙
Max Speed Overpass is a web map that shows maximum speeds. The goal of this web map is to show max speed and edit this from this map using you favorite OSM editor. The data shown is always up to date because it uses overpass query.
- ITO Map↙
ITO Map  is a map overlay service from ITO. The layers cover different data types: Barriers, Buildings and addresses, Car parks, Electricity distribution, Fixme, Former railways, Layers, Metro, Navigable waterways, Railways, Schools, Speed limits km/h, Speed limits mph, Tracktype, Unknown roads, Water.
In addition to the above error and bug reporting tools, there are a number of tools that allow you to spot erroneous changes and edits. For example if you are very familiar with an area and have thoroughly mapped it, you might want to follow all changes and verify that no unintended damage or vandalism has happened in the area. Planet History includes all changes that have been made, but might not be as easy to use. The following and other tools also listed on the Maps page.
- OpenStreetMap Watch List↙
OWL (OpenStreetMap Watch List) - Watch what is happening in OSM in a special area. Currently featuring: the new History tab
- ITO world OSM Mapper↙
- Real-time change following↙.
Currently nearly the same content: List of OSM based Services#Live/real-time edits to OSM data
- LiveEditMapViewerJ is a java program that allows you to follow changes as they happen on a world map.
- OSMZmiany is based on LiveMapViewerJ but has some additional features.
- Khtmlib - khtml.org ticker allows you to follow changes in realtime on a slippy map and get additional data about them.
- achavi - Augmented Change Viewer: visualizes updates to OpenStreetMap based on minutely Augmented_Diffs provided by Overpass API
- History Browser↙
virtuelle-loipe's History Browser with diff tool for single nodes/ways/relations (side by side comparison of two versions).
- Mapki's Deep Diff↙
- OSM Deep History↙
http://osmlab.github.io/osm-deep-history/ - diff tool for single nodes/ways/relations (but without nodes of ways and does, currently, not work for relations). Showing all versions in a table.
- History Viewer↙
OSM History Viewer shows changesets in a visual way, highlighting object positions before and after a given changeset, and also highlighting modified objects that were not moved.
- OSM Aware↙
OSM Aware feeds OSM changes as KML files.
- Historical Coverage↙
Historical Coverage service creates animations of the historical development in a specific area. (service no longer active)
UserActivity Statistics and maps of user activity in two osm files. Possibly detect vandalism... Reports (for Germany) generated periodically.
The WhoDidIt: OpenStreetMap Changeset Analyzer analyses what was changed in your area. You may need to select "month" or even "half a year" for the "age" parameter to see edits; display could take some seconds. Features an RSS feed to get informed about new changes.
- RSS History Filter↙
RSS History Filter filters out large changesets from RSS feeds generated from the OpenStreetMap history tab.
- Migurski's Changepipes↙
Migurski's Changepipes which also gives you RSS feeds of changes for an area (after manual signup via email).
- OSM control tool↙
http://osmct.de – monitor free defined polygons and mail on changes
- Traffic Sign Tool↙
Traffic Sign Tool - Assistant to get the right tags for German road signs.
QualityStreetMap () is a large grid for coordinating mapping work. You can select a tile and mark it complete for a specific tag. The grid covers the whole world and any tag. To edit the grid you have to log in with your OSM account. Zoom in to see the grid (min zoom level 12). The service is in beta.
- Navigation Debug Map↙
NavDebugMap - Slippy map showing maxspeed, turn restrictions and other routing properties.
- Road lists↙
Users in Germany requested different official lists: Straßenverzeichnis.
Check The Monuments! More Quality for the Key Monument.
- Overpass turbo↙
Overpass API and the interface Overpass turbo lets you easily create custom queries which can be used to detect potential errors. The results get shown on a map with object detail links in popups and can be easily opened in JOSM. The example page lists some quality assurance uses.
To compare the use of a tag or to see typos, use these statistical tools. See also: Stats.
Taginfo is a system for finding and aggregating information about OSM tags and making it browsable and searchable.
TagWatch - Browse tag statistics
Tagstat - Search for tags and their use.
- ITO Map↙
ITO Map () is a map overlay service from ITO. It runs scripts that highlight specifics tags which shows how consistent, or not, use of that tag is. It displays groups of related tags simultaneously.
- File:Osm-planet-1.jpg - Picture of OSM coverage.
- TIGER fixup/250 cities#Maps - A coordinated push to fix some basic routing problems in the U.S.
- OSM QA App - allows you to lock areas so as to avoid conflicts when doing teamwork.
- T@h heatmap - Coverage as heatmap.
- Reports: Unmapped Places in Europe 11/2011 and in Germany 8/2010
- OSMatrix - overlay of OSM activities, data density, historical development and further indices.
- See also: Research
- SotM 2010 session: OpenStreetMap – Ready for business!
- Bachelor Thesis comparing OSM 2009 with Navteq datas (german)
- SOTM2010 - Logiball - OSM Spain vs. commercial data compare
- Report OSM Quality Evaluation in UK 7/2007
- OSM vs Cartociudad: A study of the quality of OpenStreetMap mapping for the city of Lleida. 8/2012 (spanish)
- Paper in Transactions in GIS comparing OSM and the official Austrian reference graph in 12/2012