Quality Assurance Tools script

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This script can be used in JOSM to download errors from different error detectors, show them as markers layers and check them one by one.

Qat script logo.png

qat_script.zip v0.5.3

older release v0.5.2

Release changes.

See this page for installation/updating.


  • Errors download of currently observed area in JOSM, from different error detectors. The type of error can be selected from a menu or a toggle dialog, in the second case, multiple kinds of error can be downloaded at once.
  • Progressive correction of downloaded errors (next, next, next...).
  • Automatic flag to server (KeepRight, Osmose) of false positive errors or information gathering for manual report (OSM Inspector, Errori in OSM Italia) to the tool admin.
  • Flag errors to be ignored. They will be stored on a local black-list file and not shown to the mapper again.
  • Clickable markers for zooming/downloading a specific error. The level of the clicked marker must be activated.
  • A favourite area can be set so that only errors within it will be downloaded. It can be a ractangle, a polygon drawn by hand or an administrative boundary with specific tags.

Supported QA Tools

Tool Max number of errors downloaded Flag false positive Flag corrected error Download multiple kinds of error
OSM Inspector [1]
(not all checks, by GEOFABRIK)
None No No Yes
KeepRight [2]
(by Harald Kleiner)
10000 Yes Yes Yes
Osmose [3] 500 Yes Yes Yes
Errori OSM Italia Grp [4]
(by User:Groppo)
None No No No

How to use


From the "QA Tools" menu

Qat script menu.png Qat script error layer.png
1. Zoom with JOSM to the zone of your interest, 2. select the type of error from QA Tools menu. 3. Downloaded errors will be shown as a new layer.

From the toggle dialog

Qat script dialog.png Qat script editing.png
1. Zoom with JOSM to the zone of your interest, 2. menu QA Tools -> Quality Assurance Tools
The toggle dialog appears where you can select the type of error.
3. Fix the errors in sequence using the Go to next error button.

Correcting errors in sequence

  1. Qat script downloadBtn.png Download the errors of the selected zone (also by double click on a check name),
  2. Qat script goToNextBtn.png start correcting them one by one.
Qat script buttons.png
Qat script downloadBtn.png Download the errors of the currently observed area.
Qat script notErrorBtn.png (KeepRight - Osmose)
Flag this error to the server as a false positive.
(OSM Inspector - Errori OSM Italia Grp)
Gather information of this error on QA Tools -> False positive menu, to inform the admin of the service.
Qat script ignoreBtn.png I don't know what to do. Don't show me again this error and go to the next.
Qat script correctedBtn.png (KeepRight - Osmose)
Flag this error to the server as corrected.
Qat script goToNextBtn.png Go to the next error.

Favourite area

When the favourite area is active, only errors within this area are downloaded.

Warning. If the tool has a maximum number of errors that can be downloaded (10000 from KeepRight, 500 from Osmose), it may happen that not all the errors are shown, depending on the area shape and errors position.
To be sure that all the errors are downloaded, download them again after having corrected some of them or choose a rectangular favourite area from Preferences.

For example (see image), suppose there are 80 errors in the favourite area. The script downloads a maximum of 100 errors (green) from the rectangle (bbox) and shows to the user only 60 of them, falling inside the area (40 fall outside, top right). After 20 of 60 errors area corrected it will be possible to download the remaining 20 errors (red).

Known bugs

  • If all the layers are removed, the toggle dialogue can't be activated again from "QA Tools" --> "Quality Assurance Tools". To make it visible again click on "QA Tools" --> any tool --> any check (this will call again Main.map.addToggleDialog(self.dlg)).


Author: Groppo

Note. I wrote this script because I could not find a JOSM plugin which could fetch errors from multiple QA tools. I just know a bit of Python and I would be happy if this code could be used or could inspire someone to create a regular Java plugin with these features, or to extend an existing plugin like OpenStreetBugs or MapDust Plugin.


Gubaer, Scripting Plugin and kind help
Harald Kleiner, KeepRight
Authors of Osmose
Openstreetbugs Plugin
thanks to those who contributed with bugs tracking, testing, hints and translations. Their names are in CONTRIBUTORS and CHANGES files.

For translations, please send back to the author the file in qat_script/data/locale directory, corresponding to your language.

See also

Errors correction: