2 Deciding on an approach
There are two approaches to making sites maps presented in this guide. The main differerence between the two is in how aerial imagery is obtained:
- Using high-resolution satellite imagery.
- Using drones to capture aerial images of the site.
Source: ICRC
Each of these approaches have advantages and disadvantages and it is important to evaluate each approach against the following criteria before assessing which approach to take in your context:
2.1 Decision Matrix
| Scenario | Satellite Imagery | UAV imagery |
|---|---|---|
| A site map is needed in the fastest time possible | ✔ | ✔ |
| Very detailed imagery is required | ❌ | ✔ |
| The site is in a conflict affected area | ✔ | ❌ |
| There is persistent cloud-cover over the site | ❌ | ✔ |
| The location of the site is inaccessible | ✔ | ❌ |
| Need to build DM or 3D model | ✔ | ✔ |
| Need to conduct further analysis and thematic hazard maps (Vegetation cover analysis, Fire hazard/ extent, Flood hazard/ extent ) | ✔ | ❌ |
2.2 Information Needs
Before flying a drone or acquiring satellite imagery, it is important to be clear on what images you want to collect and for what specific purpose. Consider whether you need only an image or whether you are look to create a Digital Elevation Model, a 3D model, a NDVI index etc. as this will affect your choice in approach. Think about whether there are others applications outside of site mapping that you are in need of, such as drainage analysis, slope analysis, landslide risk analysis or vegetation cover analysis. If so, satellite imagery is a better suited imagery source that UAV imagery.
Consider what area needs to be covered whilst bearing in mind that larger areas require longer flight times, more storage etc. You should not be flying the drone above as many areas as possible to collect as many images as possible and then decide what to do with them. The data collection must be adequate, relevant and not excessive in relation to its purpose (only collect data which is needed).
However, depending on the purpose and audience of the map, it is important to capture the site’s surroundings in order to situate it within its wider context. You should not map only within the boundaries of the site. Where possible include neighbouring host community settlements, transport linkages and other key infrastructure facilities, potential hazards or environental vulnerabilities in the area.
2.3 Conflict and Data Sensitivity
Due to protection risks, the humanitarian use of drones in conflict settings is strongly discouraged. The term “dual-use technology” is commonly used to describe a technology with both civilian and military applications. With the rise of the use of drones for military use, there is a risk that the use of drones for humanitarian purposes in sites may be perceived as a security threat by the site population or cause trauma due to an association of drones with their military uses. In conflict settings armed actors or authorities are likely to perceive the flying of drones as both a security and informational risk. This means that the importation of drone equipment and/ or the request for flight approvals will likely be denied, or that their use in a site risk being perceived as a security threat. [^footnote]
There are key considerations to take into account when collecting, processing and sharing any type of data. These considerations determine the degree of sensitivity applied throughout the data life cycle and include:
- The potential to harm data subjects and others;
- The potential to discriminate;
- The potential to harm IOM staff and individuals representing authorized third parties.
In addition to the data risks and concerns outlined in the IOM Data Protection Manual, there are additional specific concerns and risks associated with the use of drones.1
Once your flight area is identified, a risk-benefit assessment should be conducted prior to using drones. The assessment will evaluate the risks and benefits associated with collecting and processing drone captured imagery and determine whether flying a drone for the collection of aerial imagery is the best approach in your context.
2.4 Data Security and Responsibility
The use of drones to capture aerial images for site mapping does not require the collection of personal data. Individuals must not be identifiable from captured images. Ensure that the flight settings (altitude, angle etc.) eliminates or reduces as much as possible the likelihood that the captured imagery may directly or indirectly identify an individual. If, by mistake, you collect images in which people can be identified, you should immediately delete them. However, if the image taken must really be used, you can either crop the image or blur the faces of people who could be identified. While collecting the data or shortly thereafter, check whether any of the images captured contains sensitive data and therefore should be deleted or otherwise removed from/made unrecognizable in the image (for example, a group of individuals that could be identified as part of a specific group, image of illegal crops or settlement).
2.5 Community Engagement
Creating Site Maps requires buy-in from the community in and around the sites area of interest, in which they are informed of the planned activity, understand how its planned to be used and why its needed and to be able to accept or reject the activity or provide inputs into how the activity is conducted or how its outputs are used.
2.6 Regulatory Environment
It is crucial to be aware of and fully understand the laws at both national and local-levels, as well the regulatory procedures and norms related to the use of UAVs, as these can vary significantly between contexts. The regulatory environment can refer to import procedures and restrictions; limitations on size and types on drones; pilot qualification requirements; and geographic limitations for UAV flight.
The Global Drone Regulations Database keeps an updated collection of country-specific regulations. It can be used to better understand the source of legal information, find relevant contact information, operating rules, as well as licensing and approval procedures. 2
2.7 Organizational Requirements
Many organizations have internal rules and guidance governing the use of technologies such as Drones. Donors may also have their own rules around their uses and the use of data resulting from the exercise. During the planning stage, it is important to contact the relevant organisation focal-point to ensure compliance with these rules.
During the planning phase, it is important that IOM staff reach out to IOM’s Office of Legal Affairs (LEG) leg@iom.int. They will provide legal and compliance guidance, as well as the latest version of the Drone usage checklist and Risk-benefit analysis template.
2.8 Level of Accuracy
In emergency contexts, the use of drones or acquiring high resolution satellite imagery of the site and its surrounding environment may not be feasible. Additionally, in the first days of an emergency, exisiting maps or preliminary spatial data on a site may not be digital (for example only photocopies of printed documents from local authorities or hand drawn maps may be available). In such cases, producing site maps with a high level of accuracy can be challenging.
Whilst low accuracy maps should not be used to conduct risk analysis such as flooding or fire hazards and cannot be used for activities such as site planning, they can still be used in for coordination purposes or as tools for focus group discussions.
Whilst there are some issues and limitations to translating and integrating hand drawn maps into GIS environments, existing printed or hand drawn maps should be digitized by redrawing features to create georeferenced spatial data layers in a GIS environment. Verifying the resulting data layers in the field can help mitigate these limitations and improve the accuracy of the digital map. One approach is to coordinate a walk-around the site where participants check and annote the map using Avenza maps (more of this in 7.2).
If neither of the above options are available and depending on the intended use of the site map and the level of accuracy required for that activity, maps of the site can be hand drawn onto large surfaces by either experienced site planners or members of the affected population and digitized at a later stage when needed.
DroneRegulations.info launched by the UAVatiors network in 2014, is a database of national-level UAV regulations↩︎