WikiProject Belgium/Building and address import

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We're working towards full building and address coverage in Belgium. We have brought together all the relevant data for Belgium in one tool that assists mapping them with JOSM. The GIM Tool is built for a slow import and for maintaining the data already imported. The tool itself is at


  • Brussels: Bulk import back in the early days. The new tool assists in updating the data.
  • Flanders: An address-only import started in 2013. Since 2016 there is a slow import of buildings with addresses.
  • Wallonia: It took much longer for relevant datasets ICAR and PICC to become open data. In early 2022, the data was added to the tool, for testing purposes only. The import procedure still needs to be started. A stub for the documentation effort already exists. Meanwhile, some power mappers have used image extraction to add huge amounts of buildings already.

Please add your work on this map. If you want to coordinate the work with a few people, feel free to use this page.

Using the tool

The tool is hosted by Gplv and is live at Instructions for using the tool and setting up your JOSM to use it are here.

OpenStreetMap Belgium DOES NOT want the buildings to be imported as quick as possible but as good as possible.

We require that you let the community review your initial work and that you stick to the quality level that we ask. You must join the dedicated building import channel first (Matrix-messaging-logo.png / #osmbe-grb), or if you don't want to join Matrix/IRC, please contact us in other ways. Failing to do this will get you blocked.

I'm not importing, what should I do about source:geometry:ref=* and source:geometry:date=* tags?

You can safely ignore them! Do not let it stop you from correcting things. When a building has clearly changed shape, just edit the building but keep the source:geometry:ref=* and source:geometry:date=* tags. Do check if your information is more recent than the date in the source:geometry:date=* tag. However, do not change that date. By keeping these tags the tool will filter this object out and prevent undoing your work, so that someone else who isn't aware that the source data is behind reality will not replace your work with the previous shape. And when the source data gets updated, the source:geometry:date=* value will change and the mapper handling an export in that area will see that the shape is changed/different as it will be present again in a filtered export. It usually means that new measurements have been taken, and chances are very high they will match your work.

Want to know more?

The source:geometry:ref=* tag refers to the object number in the imported source. The import tool will first load OSM data to see which buildings need to be imported. It uses the ref and date tags in OSM to compare versions:

  • If there is a more recent data in the external source, it will be flagged for re-import.
  • If there is no ref tag on the OSM building, it will be flagged for initial import.

So, if you remove the ref/date tags, the building object will be offered for import again next time. The importer will then look at your work and keep the best elements of both datasets. The importers should never delete existing buildings, but instead just update existing buildings. This keeps the history and avoids losing information that was added before.

There's some special values you can use to show a building shown on the official background map is outdated, missing or does not exist anymore. Their use is explained here.