WikiProject Belgium/Building and address import/AIV GRB building import
We're importing buildings in Flanders (Belgium) from a database called GRB, published by government agency AIV.
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 (irc.oftc.net #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./
The tools are available for everyone, with specific guidelines in order to achieve optimal quality. We are not dumping data in OSM but look at the data critically and compare with different sources to ascertain that it makes sense (the government address database CRAB, aerial imagery, street-level imagery, surveys...)
- Documentation about the process and technical aspects
- Background information about GRB, AIV and CRAB
- Table of how the import guidelines are fulfilled
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.