Organised Editing/Activities/Crowd2Map Tanzania

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Tanzania has a very high incidence of Female Genital Mutilation, extreme poverty, early marriage and Gender-Based Violence. NGOs on the ground need better maps to facilitate their outreach work and protect girls at risk of FGM, as well as to aid community development.





Crowd2Map slack channel





Tools and Data Sources

For remote mapping

  • Imagery: Esri, Digital Globe, or Bing.
  • ID Editor:
  • JOSM:

For groundmapping

  • OSMAnd
  • fieldpapers


  • UN Volunteers
  • Missing Maps Volunteers
  • Local Community Mappers
  • Local YouthMappers chapters
  • HOT Corporate Mapathons

Measuring our Success

Success is measured in number of features added to the map

Number of buildings KM of roads KM of waterway Number of local POIs



Please use clear satellite imagery, choose Esri, Digital Globe, or Bing imagery from the background menu Cloud cover or resolution is often an issue in Tanzania, view several sources to ensure all buildings are identified Please trace buildings from the satellite images. Please do not trace over the top of existing buildings Some Task areas will not have buildings - This is ok and important information, please just mark them as "Completely Mapped" and select another Task Square. Most Commonly used tags: building=yes


Please accurately outline all the 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. Please do not generalize or stylize the building, the building size is used for population estimates, so please be as accurate as possible. For square or rectangular buildings, after drawing the outline, use the 's' key in the web editor to "square" the corners. -or- right click on the building and choose the 'Square' option In the iD web editor, the first time you map a building you will use the "Building" category and then at the top of the list select "Building" again. If the building already exists make sure it is square, but do not trace it again Please do not snap the corners of buildings to other features such as roads and paths For rectangular buildings: In iD: draw an area and label it as “Building”, then correct for right angles with the “S” key. Animated gif of round building in iD In JOSM: To start drawing buildings, select the B key shortcut. For each bulding to add, we trace a line on one side of the building with two clicks then we slide the mouse to the opposite side of the building and we click to confirm adding the building. The tag “building=yes” is automatically traced.. To stop tracing buildings, we select the S shortcut.

For circular buildings:

In iD: draw a triangular area over the building and use the tag "Building", then correct to make the shape circular with the "O" key. Animated gif of round building in iD In JOSM: Select the Ctrl-Alt-B key shortcut the show the BuildingTools plugin options and select the Circle option. The same shortcut is used to step back to the Rectangle option. For each round building, draw the diameter of the circle with two clicks on each side of the building. This automatically trace the building and the tag “building=yes” is added.. To stop tracing buildings, we select the S shortcut.

Clean Up - Validation

Every completed task is analyzed by the validators, following the Tasking Manager steps, Osmose is also be used to identify and correct the remaining mistakes.? For HOT corporate mapathons, HOT will be responsible for validation


Some results will be posted here after the mapping is over.