Opportunities for UAV mapping to support unplanned settlement upgrading

The effort to improve sub-standard living conditions in unplanned settlements is often hindered due to a lack of adequate spatial information describing the baseline situation and changes occurring during and after the upgrading process. Low-cost Unmanned Aerial Vehicles (UAVs) could provide very detailed, up-to-date spatial information for small unplanned areas as and when required. To investigate the utility of such platforms in settlement upgrading, UAV flights were conducted over approximately 150 ha of unplanned settlements in the City of Kigali in May and June 2015. These activities were supplemented by an analysis of the spatial information needs of various stakeholders involved in the upgrading project. The UAV imagery could replace the 2008 25 cm ortho-imagery by up-to-date 3 cm imagery in current workflows for map updating. Moreover, it also enables the extraction of additional information which was previously unavailable, such as detailed elevation data to support surface water runoff analysis and drainage capacity calculations.
When using UAVs it is also important to take many practical considerations and the societal context into account. The lack of a legislative framework, the requirement for specialized knowledge, and heavy computing requirements of data processing are factors to be addressed when using UAV technologies in this setting. First experiences in Kigali have indicated that while not generally perceived as a problem by the local population, fear of forced displacement and expropriation may raise concerns amongst the residents. Communication with the population before and during flights, and sharing the benefits of the acquired information are important to mitigate these fears.