#1151 - Missing Maps: Porto Novo, Benin (task 3) (Archived)

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This project was archived.

  • Author: Missing Maps
  • Requesting organization: Netherlands Red Cross
  • Priority: Medium
  • Satellite Imagery: Mapbox satellite

The Netherlands Red Cross is supporting Croix Rouge Benin to decrease the number of children under 5 suffering from waterborne and oro-fecal diseases in the boroughs of Kessounou (common Dangbo) and Zoungamé (common Aguégués) in the department of Ouémé, Benin. One of the activities to achieve this is to perform field assessments that identify vulnerable people. Detailed maps of the project area are vital to properly undertake the assessment.

The Netherlands Red Cross will also start investing in a local OSM / HOT community in Benin and is seeking opportunities to provide the necessary training and resources where needed.

The Missing Maps project aims to map the most vulnerable places in the world (affected by humanitarian crises: disease epidemics, conflict, natural disasters, poverty, environmental crises). Building on HOT's disaster preparedness projects, the Missing Maps tasks facilitate pre-emptive mapping of priority countries to better facilitate disaster response, medical activities and resource allocation when crises occur.

Created by pedrito1414 - Updated - Priority: medium


Entities to Map
residential roads and buildings
Changeset Comment
#MissingMaps #Benin #Porto-Novo #hotosm-project-1151 #RodeKruis #kadaster
When saving your work, please leave the default comment but add what you actually mapped, for example "added buildings and a residential road".


Please click on a square to start mapping. Make sure you read below how to adjust the imagery offset before starting to map! Also read the task instructions on how to map roads and buildings.

Satellte imagery

Please use the Mapbox satellite imagery, which is recent and high quality.


Simply trace the outline of all buildings. A building should be tagged as a Building of type Building (because we don't know the exact function of that building from satellite imagery). Make sure you SQUARE (shortcut key = 'S' in iD editor) the corners of square/rectangular buildings.

Trace any missing roads within the city. A road within the city should be tagged as Residential road.

Cloud cover

There is considerable cloud coverage on the Worldview-3 imagery. Please trace whatever is possible. If you cannot finish the tile due to cloud coverage, switch to Worldview-2 imagery as described below, or alternatively to Bing Aerial Imagery. If with neither of these three sources you can successfully complete the tasks, then save your changes, mention 'cloud coverage' in the comment when you save the task,and mark the task as done.

Switching satellite imagery

If you want to switch imagery, go to the Background settings in the ID-editor, click Custom and replace the url with one of the below. Then apply the new Imagery offset by going into the Background settings. Open the 'Adjust imagery offset' tab and copy & paste the imagery offset mentioned below for the new imagery.


We kindly request advanced mappers and validators to contribute to validating the work of others. This task can only be completed when all tiles have been marked as validated (green). To validate, choose a tile marked 'done' (orange) and click 'review the work'. Open it in JOSM or the ID-editor. Correct any errors such as:

  • Map missing roads and buildings.

  • Correct wrong imagery offset compared to the Bing Aerial Imagery (which is the standard for OSM). In this case shift all buildings at once in JOSM (if all are misaligned), or do them one by one.

  • Correct buildings. Some buildings are not properly drawn. See if you can correct them to match the shape of the building on the satellite imagery. If a building is not squared but should be, apply squaring to the buildings (this is most easily done in JOSM where all buildings can be selected and squared with one click.

  • Correct roads. Some roads will be misaligned against the Bing Aerial Imagery, or just misinterpreted.

If you finish validating a tile. Save your changes, mark it as validated in the HOT tasking manager, and leave a comment to the original contributors i.e.: 'thank you for mapping all these buildings and roads. We made a few corrections. Please consider squaring the buildings in your future work, and make sure that you don't miss any'

Further tagging resources

See Highway Africa Tag page for further advice on tagging roads and the OSM map features page for more info.

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Contributors Done Assigned