Methods
More often than not, maps are developed remotely by cartographers with great knowledge in their field, but no physical experience within the field that they are mapping. This results in inaccurate and insufficient data. For reference, see the two conflicting maps of one location in Dar es Salaam pictured to the right.
Ramani Huria does it differently. We train local university students and community members how to effectively create sophisticated maps of the city within which they live – maps with more than enough detail to serve as guides for all realms of development, with a particular focus on improving flood resilience.
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Data Collection
The first goal of Ramani Huria is to equip community members with the skills required to conduct mapping. In order to do so, we begin by educating project participants about open source data collection tools; OpenMapKit and OpenDataKit.
OpenMapKit and OpenDataKit are intuitive phone applications that are equipped with imagery and forms for direct data collection while in the field. Equipped with a smartphone app and internet scratchcards, and supported by the Ramani Huria team, community members and Wajumbe (community leaders) are able to collect data at a hyperlocal level using these digital surveys. The data they collect and infrastructural features that they tag are contributing to the most detailed map to ever be created of Dar es Salaam.
Aerial Imagery
Before Ramani Huria – the aerial photography for mapping in Dar es Salaam was dependant on minimal to no cloud cover, or alternatively was of low satellite quality.
To combat this, and to ensure the highest quality of imagery for the community mappers, we employ drones in collaboration with Drone Adventures and the Commission for Science and Technology COSTECH. The difference in detail enabled by these tools is astounding. For reference, see this comparison between a map produced with and without the new aerial imagery.
Before
After
Drainage Mapping
The Ramani Huria project has not stopped at mapping roads and buildings. Going even further to help mappers create richer and more detailed maps to use for flood prevention initiatives, the Ramani Huria team have conducted drainage mapping of the city.
The drainage system in Dar es Salaam is enormous and complex, with hundreds of thousands of drains, often alongside roads, ranging from enormous 3-metre-deep concrete channels along highways to 5-cm-deep hand-dug ditches draining individual home sites. To help reduce flooding, drainage measurements and observations were taken to help identify problem spots where drains needed repair, redesign, or cleaning.
As of January 2018,we have completed the field mapping, quality checks, and data cleaning for the drainage systems in twelve wards of Dar es Salaam. These twelve wards have all been quality checked using the Deltares Hydro – OSM tool (https://github.com/openearth/hydro-osm), a toolbox to convert OpenStreetMap data into data layers that can be readily used for hydrological and hydraulic modelling and generation of a topologically correct 1D network.
