Eastern DRC & Western Uganda Maxar-Ecopia Buildings Import
The Eastern DRC & Western Uganda Maxar-Ecopia Buildings Import is an import of building footprints covering the north-eastern part of the Democratic Republic of the Congo (Ituri and North-Kivu provinces) and the western part of Uganda. The import is currently going through the Import Guidelines steps, and it should be soon an ongoing crowdsourced task.
The Humanitarian OSM Team and its community has the goal of importing these building footprints into OSM in a crowdsourced way, merging them with the existing data, improving their geometries when needed, and dismissing those that aren't correct - using aerial imagery for validation.
More detail on the context of this project can be found on this page.
The original data is in shapefile format, and consists of around 6.6 millions building footprints across the north-eastern part of DRC (Nord-Kivu and Ituri provinces) and the western part of Uganda. MAXAR has given permission to import the data into OSM.
Data has been generated by automated feature extraction based on MAXAR imagery performed by Ecopia AI and funded by the Humanitarian Grand Challenge. The main feature extraction and data validation was mainly performed using training sets from the area etc.
All building footprints could be imported into OSM, except when existing buildings were traced or created from a more recent source. In the cases where there are existing buildings footprints traced from older imagery, the MAXAR-Ecopia building footprints will replace the older ones, keeping the history as much as possible, and hence improving the OSM database.
Data source site:
OSM Data Files
The best approach to import this data is manually by the community, with data split in a number of files, that will correspond to an equal number of projects in the HOT Tasking Manager. Advantages:
We will provide a link for each Tasking Manager project in a table of the import workflow wiki, with info about the total size (number of buildings) and expected time of work for each one. We will open the different projects progressively, when the previous jobs are being finished.
Data reduction & simplification
No simplification of the original data is expected.
Some of the tags of the original dataset aren't relevant, so we ignore them. Here we list all the original tags with their corresponding translation into the OSM tagging schema, plus additional tags for all segments:
Data transformation results
We will use the following changeset tags:
Tag automatically added by the Tasking Manager:
where NUMBEROFPROJECT is the Tasking Manager project number.
Tags to be updated or added manually:
Data merge workflow
This import (data integration) will be done through the HOT Tasking Manager, so the number of people importing the data is unknown. We don't expect a big number of users, as we require them to be experienced mappers. Among the skills required:
Following the imports guidelines, this import has been discussed first in the local DRC OSM mailing list, local Uganda OSM mailing list, and to get more feedback it was also shared with the HOT mailing list.
We will use the JOSM editor for this import.
Step by step instructions
There are several ways to reach the same results. We have tried to find the simplest one, the less error-prone and the one that assures a higher level of consistency across different import volunteers. The proposed workflow is as follows:
Changesets will be small in size, so no issues expected in this respect.
If something goes wrong (quite unlikely based on experience), JOSM reverter will be used.
Conflation is explained in the import workflow wiki, in the sections 3.2.2 and 3.3.
The import workflow will basically keep the tagging and the geometries of the existing OSM buildings, unless the Maxar/Ecopia equivalent is of better quality or simply more correct. All existing tags will be preserved.
If an existing building in OSM is no longer visible on the most recent imagery (theoretically the one provided by Maxar unless the existing building was traced on customized imagery), it will be removed unless it contains any valuable tags but a fixme tag could be added to it.
We will also make sure buildings and highways don’t cross each other.
Acknowledgement of other organized editing and imports
Since several mapping teams are currently active in the region, we acknowledge being aware and coordinating with other teams including:
Validation of the import will be done by a second user in the Tasking Manager.