Reveal Residential Buildings Mapping

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  • This Project was started on 27th August, 2018 and was/is estimated to last for about 5-6 weeks.
  • 2019 had two mapping sessions, the first session was between February 13th and April 16th, the second mapping mapping session started on 1st July, 2019 to last about 6-8 weeks
  • 2020 has had three mapping sessions. One started on 23rd March and completed on 15th April, the current two active mapping sessions are still ongoing. One started on 8th May 2020 and scheduled to be completed in 6-7 weeks. The other active mapping activity started on 15th May scheduled to be completed in 3-4 weeks.


  • The scope of this project was 8 districts across 3 provinces in Zambia in year 2018
  • In 2019, 15 districts were mapped from 5 provinces in Zambia and 30 districts from all provinces in Rwanda
  • In 2020, 13 districts are being mapped from 3 provinces in Zambia and 4 districts from Senegal namely Linguére, Ranerou, Kanel and Matam


An effort to map all residential buildings from areas of interest to be used as data collection points during the implementation of different household surveys including Indoor Residual Spraying and Mass Drag Administration in the fight against Malaria using the Reveal tool.


Mapping is being organised by Akros with local trained mappers having vast field knowledge of both rural and ubarn parts of Zambia. Senegal is being mapped by getting local context from our in-country partners. The main coordinators and contact persons at Akros are Derek Pollard, Frazer Bwalya, Ernest Mulenga and James Nyirenda (Derek Pollard -, Frazzy -, A~nest -, J@mesN - respectively)



Mapping is done using privately licensed DigitalGlobe evwhs imagery not available to other mappers.


The alignment might not match any of the available sources on osm in this case the following is/has being done

  • Where no building mapping has been done yet - mapping aligned to evwhs imagery
  • Past mapping has been done - existing buildings with varying alignment is/were aligned to evwhs imagery

Task Management

Task management is done using private HOT Tasking Manager projects with the following instructions;

  • Reveal Mappers Only
  • Please accurately outline all possibly residential buildings you can find. The outline should be for the full size of the building even if it is partly covered by trees in the imagery.
  • Most buildings are rectangular, after drawing the outline, use the ‘q’ key in JOSM editor to "square" the corners.
  • For circular buildings use 'o' key on your keyboard to create a circular structure.
  • Many buildings are very close, but do not actually touch each other, try to map them close to each other without letting them connect or share nodes with each other, roads or land use area outlines.
  • Tag residential buildings as building=residential and leave all non-residential as building=yes and add source=akros tag. Differentiating residential from non-residential should be based on the training all mappers included to contribute to this project received which was based on local field experience enough to make a correct judgment of residential structures from a satellite image.

Example project here

JOSM is also setup with filters to prevent accidental edits on anything that is not a building;

  • type:way building=*