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Since 2016-05-01 the frontend server is currently down due to lack of admin time, a fallback can be to use instead.

It is provided by the French "association" (fondation)

Key functionalities

  • Provide a slippy map with image layers to help people find possible errors in the data (Quality Assurance)
  • Provides layers with roads having no name, no ref, no oneway; Drawing fixmes and notes texts; and layers showing administrative surface by admin_level.
  • Coverage : world
  • The database is updated almost in real time (the db's date is written at the bottom), and tiles should also be mostly live thanks to osm2pgsql's dirty tile list feature.

Where to find it or information about it?

* The tool is located on

Base layers

  • There is a less and less basic Openlayers showing you the map
  • Base layer is changing every now and then
  • overlays are generated from the database's copy and can be up to 24h late
  • Database is updated from minutes diff so it shouldn't be too old (check the last DB update date at the bottom of the tool's page)


Overlays layers (mostly about highway=*)

no name overlay

This layer shows a red line on those features without a name=* tag.

This tool take advantage of the Proposed features/Internal quality adding validate:no_name=no_sign and validate:no_name=yes will stop displaying the colored line.

no oneway overlay

There is a purple line on :

  • unclassified/residential/minor/road

When there are no oneway=yes or no oneway=no tag to the highway. (Keep in mind that it does not mean there is an error, it is here to help survey cities for oneway streets)

no ref overlay

There is a blue line on :

  • tertiary/secondary/primary/motorway

When there are no ref=* tag on the highway

To avoid false positive this tool take advantage of the Proposed features/Internal quality validate:no_ref=no_sign or validate:no_ref=yes value

fixme/notes overlay

  • An overlay is available to display the text of the fixmes and notes

Notes-map.png notes Fixmes-map.png fixmes

my_own overlay

There is a purple line on :

  • unclassified/residential/minor/road

When there are a validate:my_own=yes (should be extended later to work with any other ways )

Administrative overlays layers

Note : If you are not aware of OSM Inspector I do recommend to give it a try as it is much better though of for geometries detections errors (with direct edit link and much more)

There is a representation of correct (as it imports well with osm2pgsql) relations boundaries. Not colored area have a problem :

  • Not closed
  • missing a tag
  • missing a name

It should respect the proposed : Boundary relations with the use of type=multipolygon OR type=boundary (both are considered correct)

Note however that this tool is only good as an overview of an area, it doesn't tells you where the problem is and what exactly the problem is. If you want a better analyse of a relation you can use :


Filled with one color when the relation is complete and okay.


Shown in red/orange/yellow or green when the relation is good.

Due to data size restrictions, color based on last modifications are not shown anymore, the 4 colors choice is now only based on the OSM ID number and an arbitrary formula to simulate the creation age (see styles)

Also, areas are shown in gray when there is a topology error : singularity like self intersecting, backward ... (Only active on zoom 12 and more for server load reasons)

Admin level8 map.png

Ways with admin boundary

  • A layer displays ways tagged with boundary=administrative with some fancy/random colors for some admin_level values, and black for all others, this helps find orphan ways (not member of a relation, or not member of a valid relation)


Support for "super-relation" (relations having relations as members ) (I hope that osm2pgsql will support it one day)

Download styles

All my mapnik styles are available to anyone for any purpose. (They might not be optimal at all, feel free to send me back patch if you find ways to improve them)

Just ask me

DISCLAIMER : Don't blame me if, using it, any form of life surounding your house is brought to an end after your computer has melt.

Comments / questions / bugs

You can use the bug tracker using the "layers" component. (Sometimes more suited than a wiki page for feature and bug requests) : Open anonymously a ticket (or after authentification)

You can also use the FR talk:Servers/

Those pages are in my watch list, so I will receive an e-mail if you write something in it and if you remove the "minor" flag of your edit, wich is set by defaut when someone edit the page, and no e-mail are sent.

See also