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Reliable crowdsourcing in the times of disasters

A smartphone app supporting crowdsourcing and geo-referenced images helps in improving disaster assessment

A collage of photos from the ASIGN server

During the 2011 Thailand floods, the world’s fourth costliest disaster, over 800 people died and 77 provinces were declared as disaster zones. When the flood approached larger cities, and specifically Bangkok, a larger disaster was imminent. Frequent and accurate flood observations were needed as much more was at stake.

The problem
Periodically updated flood maps based on radar satellite images were provided by UNOSAT every few days. However, while the importance of up-to-date monitoring of the flooding in the city areas increased, the quality of radar observations reduced (due to increased backscatter/ noise from objects and infrastructure), sometimes leaving it to satellite images alone to determine if areas were flooded or whether they were reflections from flat wet surfaces.

Leading the FP7 SPACE Project GEOPICTURES, AnsuR, a Norwegian technology developer for visual situational awareness, collaborated with the United Nations (UNOSAT), and suggested a smartphone app for crowdsourcing reliably time- and geo-referenced in-situ images for the purpose of improving disaster assessment from earth observation (EO)images.

The results
For years, AnsuR has worked with efficient mission-critical communications of geotagged pictures, including using professional cameras and a specialised smartphone application as a tool for communicating photos quickly and reliably. In May 2011, a few months before the Thai floods, AnsuR released a crowdsourcing version of the ASIGN application for UNOSAT. However, following the floods, AnsuR opened this application for public use in Thailand, in order to provide input to the validation of satellite images as well as to allow other use of the input images.

Over the following months, close to 1,000 geo-referenced photos from the greater Bangkok area came in to the AnsuR server, and was shared with UNOSAT, who were able to provide better flood maps, that in turn helped authorities in managing the disaster better.

The Thai government, the Asian Disaster Prevention Center and Google used them in disaster management. GEO-PICTURES/ASIGN has even won the 2012 GMES masters competition in the ESA App Challenge Category.

Map from the UNOSAT GIS server where the red area represents flooded parts

The technology
The ASIGN app sends geo-referenced images quickly and reliably from the field to an ASIGN server at CERN over even unreliable networks. ASIGN offers image analysts access to full photographic details, to focus on image with relevant content that can have impact on the operations. The system supports using any satellite or mobile communications.

The full ASIGN system is a client-server concept, with field SW for PC, linux computers and smartphone. The professional app is available for Android, while the crowdsourcing version is available for iPhone, Android and Windows 8 phones, and is based on professional disaster assessment tools. It makes use of satellite navigation systems and smart protocols for minimising bandwidth requirements and transfer time, while maximising robustness towards unreliable links and preserving access to full image quality.

The unique features of ASIGN include reliable and consistent information. It gets accurate satellite time- and geo-tagging, and only allows photos to be taken via the app itself, effectively eliminating chances of editing or importing data when it is received seconds after capture. In order to contribute, users have to register, and provide name and number. Information is in general received seconds after capture, so it is available fast. There is no need to worry about remembering where to send it.

As a compressed photo is sent initially, ASIGN protocols allow analysts to automatically request a full resolution region of interest from the sender. In this way, communications are optimised at all three levels: technical — by using efficient compression, content — by allowing focus on what is interesting, and impact — by prioritising resources on what is relevant for the operations. The photos are available via a Web interface from anywhere in the world. Observations can be allocated to a GeoRSS feed or integrated with maps. The maps can also be updated with latest images.

In addition to photos, ASIGN provides support for geo-tagged free text and structured assessment templates, that can be created dynamically at the ASIGN server via a Web browser. Also time- and geo-tagged video clips, voice captions and text messages are possible.

UNOSAT also has the QR code for the app on its website, but now all the Apps for Apple, Android and Windows 8 are found in their respective application stores.

The ASIGN technology is still used with professional in situ validation photos, sent via smartphones, PCs, satellite or 3G or other means. In this context, the use of small unmanned aerial vehicles is interesting, and AnsuR recently demonstrated ASIGN in UAVs at a workshop organised by the UN and EU in Geneva. In this context, crowdsourcing can also complement aerial observations.