Municipality boundaries in Attica. Is there something wrong?

Hi everybody,

I’m currently preparing an exposure model for Attica. This model is describing all buildings and their vulnerability to earthquakes. In order to do this, I am associating each building in OSM to the municipality it is located in. While extracting the municipality boundaries in Attica from OSM, I noticed two major discrepancies to the boundary data from (I do not refer to gadm being imprecise but the boundaries being vastly different):

  1. According to OSM, the island Agios Georgios seems to officially belong to the municipality of Lavreotiki but in the OSM it is associated to the
    municipality of Hydra. GADM and associate the island to Lavreotiki and so I tend to believe that this might be correct. If so, it would be good if there is a consensus to associate the island with Lavreotiki instead of Hydra.

  2. In OSM I can find the boundary of Δήμος Τροιζηνίας (admin level 7 like all other municipality boundaries in Attica) but in GADM and the aforementioned website, this area is split into two municipalities: Troizinia-Methana and Poros. Again, the other source agree and contradict OSM.

Can anybody help me figuring out what the correct and current boundaries are and fix them? I’m happy to fix problem 1 but if problem 2 needs the import from the website, I’d prefer this to be done by somebody who understands Greek in order to avoid a copyright issue that may arise from me not understanding the text on the website.

Thanks a lot for your help!

Cheers from Berlin, Germany


Agios Georgios has a long history, used to belong in Hydra, then appears as part of Lavreotiki (in 2011 census)
since then the 2 municipalities are fighting over the island in court

apparently the municipality that gets the island will get around 1million because of the wind turbines

The Troizinia status is somehow clear, there are 2 municipalities:troizinia-methana and poros, someone forgot to divide them

Thanks a lot or the explanation. I see where the issues are coming from. However, a few questions remain, in particular about how to move forward:

  1. I can re-assign Agios Georgios to Lavreotiki if the current (even if debated) state is that it belongs to Lavreotiki. I would of course feel more comfortable if someone with more local knowledge does this. Is it even consensus that Agios Georgios is currently part of Lavreotiki? The fact that the municipality of Hydra is challenging this in court seems to at least confirm that they agree that it is currently associated with Lavreotiki (which they try to change).

  2. Splitting Troizinia is not that simple for me. Again I’m happy to do this if somebody can point me to boundary data that is openly available and can be used in OSM.

Is there maybe somebody who has feels responsible for the boundaries in Greece?

Cheers and thanks for your help!

The issues are solved!

Thanks to everybody who helped out!