syntex's Diary

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1000 mapping days!

Posted by syntex on 15 April 2022 in English (English).

Replacing all buildings in Warsaw - challenge

Posted by syntex on 13 July 2021 in English (English). Last updated on 27 July 2021.


Since the 31st of August 2020 a huge polish government database BDOT10k, which contain a lot of useful data is publicly available and also can be used for the purpose of OpenStreetMap. The quality of the data varies depending on the region. Nevertheless, the quality of the buildings in this database, especially in the city of Warsaw is quite astonishing. That is why I decided, that we should make use of this data and implement it, especially that the existing buildings in OpenStreetMap in some districts of the city are just awful, made 5 or more years ago on Bing satellite imagery.

The process:

This is not an automated process, every building is reviewed one by one MANUALLY and that is why it takes so much time. I also turn on the EGIB database in JOSM, to verify the shapes of buildings and also to add smaller ones like sheds, because the BDOT10k does not contain buildings smaller than 40m2. Some detached houses, that are abandoned, also do not appear in the BDOT10k base. I do not delete building that are almost ideal, it doesn’t make any sense. I only copy the data about the purpose of the building and the amount of floors from the BDOT10k and I add it to the existing object. It makes this entire process even longer, because you have to be also a quality controler : )
And the most important, a huge thank you to tomczk known on discord also as Tomek | budynki for creating this incredible tool budynki which made the process so much easier, than manually downloading the BDOT10k data from the polish government websites. It enables downloading objects from a particular region, you do not have to download data package that contain for example the whole city or the whole “gmina”. This tool also translates all these objects from the governmental language to a OSM tags language : )

Reasons why?:

  1. Obviouse one, improving OpenstreetMap : )
  2. New users of OSM, do not really know how imagery or other things work. They see the buildings and other data and if the osm data and new, high quality imagery do not fit each other, they try to add new objects in some kind of compromise between them, so the result is that there are more and more bad quality objects. Unfortunatelly some people just resign from adding anything when they see this, they just think that it is too much work for them to handle. If the quality of data is so bad in the capital city, how bad it must be in the countryside?
  3. Encourage entrepreneurs to add their companies to OSM.
  4. Intention to stop wasting resources of OSM users on adding objects, that are already made by someone else and with a better quality.
  5. I just like Warsaw : )

The progress:

I have already completed 5 district of Warsaw: Ursynów, Wilanów, Wesoła, Rembertów and Wawer. Białołęka is completed in 70%. Other district are still waiting. Bonus: the whole village of Michałów-Grabina is also completed, because the quality of data in the BDOT10k database there was also very good

A link to the map with the progress: Progress map Map key:
* Red - Completed areas and the border of the city
* Violet - Building were already OK there in OSM, but they lack any information on their purpose or the amount of floors

Location: Śródmieście Północne, Śródmieście, Warsaw, Masovian Voivodeship, Poland