Serbia/RGZ Import
Update for January 2022: data is imported and synced with official cadastre registry. Difference between cadasters and OSM data is 0.03% for 99th percentile (0.0001% average). National borders are not 100% (as expected) and there are still some minor gaps in data. Follow OSM forum thread for further details.
This page tries to unify all resources around import of "Registar prostornih jedinica" to OSM. This data carries geodata information of all boundaries in Serbia.
OSM thread (Serbian): https://forum.openstreetmap.org/viewtopic.php?id=68288
Web app: https://opendata.geosrbija.rs/
Source code: https://gitlab.com/stalker314314/prostorne-jedinice-import
Licence
Serbian parliament ratified opening this data in 14. December 2019. (Сл. гласник РС 86/2019). Announcement can be found in Serbian cadastre agency here and web application that hosts this data is located here.
Since this is government data, license defined is here: https://data.gov.rs/sr/terms/. However, we are still actively looking to get license of this data that comes from cadasters website itself.
Work items
Defining new/updated metadata
So far, here are the changes we plan to introduce with this:
- we clarified on forum what naselja ("settlements") are (admin_level=9) and that "mesne zajednice" ("local communities") will be admin_level=10, but will not be imported at this point. So, we will focus on admin_level 4-9
- We also defined new tag "ref:sr:maticni_broj" that we plan to add on admin_level=(7,8,9), similar to German de:regionalschluessel and de:amtlicher_gemeindeschluessel
- All level relations will have associated "subarea" members, so we have proper hierarchical structure
- We also agreed that we will treat government data as "truth", even if that means there are gaps (but not including country borders)
- source for all imports is planned to be "source=RGZ_Import"
Analyzing data
Since we already have boundaries in OSM, the only thing we can do here is try to conflate and "fix" existing boundaries. So far, we are discussing potential options.
Here is OSM file with all admin_level=9 boundaries imported in OSM: https://kokanovic.org/rpj-v1.7z.
We also analyzed how much are boundaries accurate today. For this, we created software that is measuring accuracy by two metrics:
- area of intersection between OSM and cadasters / area of cadasters.
- sum of distances over all points in cadastre polygons to nearest OSM polygon
In general, results we got are excellent, with averages and 50th percentile for metric 1 of 98% (98% of area is same in OSM and cadasters today). This means that
Conflation/import work planned
Based on results of analysis, we do not plan to remove any existing boundaries and create new ways/relations. We plan to work with existing boundaries, conflating them as necessary. Currently, there are some efforts that we like to do
Adding ref:sr:maticni_broj
Results of analysis also got us relation IDs, so we can easily add them to OSM. Remaining (unmatched) relations will need to be added manually, either by finding them manually, or adding "settlement" if it doesn't exist. To ensure that we don't lose this tag, we will incorporate ability to detect and warn if admin_level 7,8,9 do not have "ref:sr:maticni_broj" tag in Serbian OSM Lint tool.
This is deprecated, we started using ref:RS:naselje, check out Key:ref:RS:naselje.
Adding subareas
Same as with previous item. We first need to match all admin_level=7,8 with cadasters data and once it is done, we can add subarea members were missing. Serbian OSM Lint tool will help to ensure this data is present in the future.
Manual procedure for fixing boundaries
Sr:Serbia/RGZ_Import/Uputstvo (Serbian)
Serbia/RGZ_Import/Uputstvo (English)
Country borders
Romania
Synced with Romania Telegram group, borders aligned.
Bulgaria
Border aligned, there were marker stones that were left unchanged. Overall, border is fixed whenever there were natural boundaries to follow (river, farms), but it is still not aligned with RGZ data completely.
North Macedonia
Border aligned. There are some gaps, but it is 90% aligned with RGZ data.
Kosovo
Kosovo recently got through this similar procedure, as described in here: https://lists.openstreetmap.org/pipermail/imports/2019-November/006113.html. When we tried to compare data from OSM files generated by Kosovo government and Serbia government, they match 100%. Only difference is around Kopaonik area at query (https://www.openstreetmap.org/way/562935476) near "Pančićev vrh", where Kosovo claims a bit more territory, but OSM and Serbian government agree. Other than that, OSM borders generally agree with both government sources, but there are some anomalies here and there. We contacted Kosovo OSM mappers over OSM forum and will continue over there.
Update: Except from 2 to 3 areas with larger conflicts (~50m), everything else is aligned with Kosovo and RGZ data.
Montenegro
Border aligned. There are some gaps, but it is 90% aligned with RGZ data.
Bosnia and Herzegovina
Border aligned. There are some gaps, but it is 90% aligned with RGZ data.
Croatia
Border aligned. There are some conflict areas, but it is mostly aligned with RGZ data, especially areas which follow natural boundaries like farms and forests. There are still parts that differ more than 50m that are not touched.
Hungary
Border aligned. There are some gaps, but it is 90% aligned with RGZ data.