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Introduction

In the fall of 2016, CartONG and the Swiss Foundation for Demining (FSD) took part in a six day training program and simulation for 13 staff of a key international organization that is engaged in the planning and management of refugee camps. The training assumed that 7,000 refugees had to be accommodated in the shelter camps on immediate basis. The major chunk of the training program was geared towards providing hands on practice to the participants on the Autodesk software.

CartONG and the Swiss Foundation for Demining (FSD), during the simulation, portrayed the use of mapping drones. The purpose was to collect aerial imagery with the help of drones to help plan a refugee camp design on 1.8 square Km of land that had been assumed to be reserved for the refugees. CartONG provided the participants with aerial imagery, a Digital Terrain Model (DTM) and a Digital Surface Model (DSM) of the area. The files were originally generated in Pix4D but were importable to Autodesk software.

It took almost half an hour to cover the entire area. Subsequently, it took another 40 minutes to create the point cloud, orthomosaic and contour lines and then yet another hour to generate the DTM and DSM. A fixed wing, eBee Senselfy drone equipped with optical (RGB) camera was used by CartONG for this purpose.

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Professionals were adamant that the availability of high quality video footage could be really handy in planning a new settlement or when planning to improve an already existing camp. The participants took a fancy to the free satellite imagery that was available through the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). However, there was a feeling amongst the participants that the image resolution of 15 to 90MP of the ASTER images was far less than that required by site planners. The participants believed that drone imagery could serve as a viable substitute to this low resolution imagery. CartONG captured aerial images at a resolution of 12 cm per pixel for the sake of simulation which turned out to be sufficient. The eBee Senselfy drone has the ability to attain image resolution of up to 3cm per pixel.Participants also appreciated the noiseless flight undertaken by the eBee in contrast to a quadcopter that was being flown by a camera team near the training site.

During the training sessions, the participants were informed that a single eBee Sensefly cost a whopping $20,000. However, a camp manager who wanted access to satellite imagery on daily basis opined that in contrast to the cost of $500 per satellite image, the costs for the drone could be easily compensated. Another participant informed the gathering that there were certain legal limitations when it came to satellite imagery such as the fact that a buyer could not share the data with all organizations working in the refugee settlement. The drone imagery, in contrast, would be owned by the drone pilot and could be shared as and when required.

Some participants alluded to the stringent regulations in place in majority of the countries with regard to drones and how difficult it was to convince local authorities to fly drones even for humanitarian purposes. Since refugees are mostly displaced by armed conflict instead of natural catastrophes, so the gathering assumed that the local law enforcement agencies would naturally be skeptical of the use of drones in and around refugee camps.

Primary Uses

One of the primary uses of drones would be to gain insight about the topography, slope and elevation of a potential refugee camp site. Here are some of the crucial information products:
• Topographical analysis based on contour lines.
• An analysis of slope and elevation.
This information could come in handy for site planners while ascertaining the amount of land that could be used and hence also predict the number of people that could be accommodated in the settlement. Coupled with the UNOSAT flood data, the site planners could also forecast the risk of floods and also incorporate mitigation measures in the planning stage.
Other uses of the data acquired by drones for site planners include:
• Generation of a map with typical services and facilities which can be beneficial while planning large sites without any maps.
• Accurate planning of drainage, water, sanitation and health facilities and irrigation mechanisms.
• A prediction of how the camps will evolve with time. One of the participants opined that this could help in forecasting if two of the groups in a settlement were moving closer to each other or moving away. Of course, this could only be predicted with the knowledge of the background of the refugees.
• The environmental impact of a refugee settlement could be documented by using aerial imagery prior to the development of the camp and then comparing it with subsequent imagery. Reforestation efforts could also be carried out this way. But satellite imagery was considered sufficient for this purpose.
• One of the participants argued that the monitoring of roads and construction could be carried out from the ground but it could be swifter with the help of drones and also save plenty of time
• The scientific rigor of household surveys could be enhanced by assisting enumerators choose a representative sample of households with the help of drone images.
One of the training participants also shared his personal experience where refugees began to move shelters within the camp as they disagreed with the design of the site or preferred to be closer to a certain group of people. This created complications with regard to monitoring occupancy. In such cases, drones could be beneficial in finding a shelter if it had a number written on its roof.
Challenges faced in simulation

Flights

The simulations took place in the vicinity of a Swiss mountain resort where drone pilots had to deal with a certain obstacle which is by no means a common sight in humanitarian response activities: paragliders. About two thirds of the target area was mapped by CartONG a couple of weeks before the simulation with an eBee drone but the large number of paragliders resulted into incomplete flights.
Heavy fog resulted into a visibility of less than 25 meters which led to incomplete flights before the simulation. In terms of cloud cover, drones clearly have an edge over satellites or manned aircrafts but the flights on the foggy day were made impossible owing to a couple of significant reasons:
•Visibility was too low for the drone to see what was coming in its way
• Visibility was too low for the operator to keep the drone in his line of sight which is a mandatory regulation to be followed in Switzerland
However, luckily enough, the weather became pleasant on the day of the simulation which allowed the CartONG crew to complete the flights just at the last minute.

Data Processing

During the creation of DTM, the large number of trees in the region posed additional hurdles. The drones were not loaded with sophisticated LIDAR sensor, so the camera was not able to view through the canopy to the ground. Also, since CartONG were employing a beta version of Pix4D which cannot automatically eliminate trees with better prowess, so the information manager had to remove trees manually from the imagery and fill in the gaps with the help of Pix4D using an approximation of elevation profile.
Technical Specifications:
Type of system: Sensefly eBee.
Deploying Agency: FSD/CartONG.
Piloting Agency: CartONG.

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