Nepal earthquake: How digital volunteers mapped affected areas within 48 hours

On April 25, a 7.8-magnitude earthquake hit Nepal with tremors and aftershocks killing over 5000 people. The same day began efforts from across the world to map the affected areas that will help with search, rescue and relief operations. After all, imagery and maps are of utmost importance to reach out and begin helping victims and survivors of a disaster. These days, it is also combined with information pouring in from social media. According to a report on Wired, the combined efforts from digital volunteers across the world have helped map the quake affected areas in Nepal in just 48 hours. The numbers of digital volunteers rapidly increased to over 2,182 and together helped with 14,700 km2 worth of high resolution satellite imagery, helping identify over 3,128 damaged buildings. [caption id=“attachment_265345” align=“aligncenter” width=“640”]  Image: DigitalGlobe[/caption] The report further details the process right from the first hour after the disaster. To begin with, mapping a disaster zone right after the calamity is ‘messy’ due to lack of data. “More data sources can be sought and added as time goes on, but from the off agencies know people on the ground will need a basic set off maps to begin their coordination efforts,” it adds. The Wired report reveals that in the first one hour Colorado-based DigitalGlobe instructed its newest model orbiting at 617km above Earth, the WorldView-3 satellite, to capture the region. Soon, the American Red Cross team in Washington DC started creating the ‘shake map’. Then, using the US Geological Survey EarthExplorer data, the map points out at the areas hit hardest by the earthquake. Meanwhile, the International Federation of Red Cross and Red Crescent Societies (IFRC) started initiating the “surge desk”, and also started requesting its international teams to help. Paul Keating from the London Red Cross team, told the news site, that the focus back then was on completing simple base maps for the field assessment and emergency response units. The maps look into the most affected areas, using OSM (Open Street Map) to identify villages in these zones. On Day 1, the American Red Cross team integrated data from the 2011 Nepal Census to clearly show the areas with most affected people in the shake map, while the International Federation of Red Cross and Red Crescent Societies answered calls for help and coordinated them with the Humanitarian OpenStreetMap (OSM) Team. They in turn with Kathmandu Living Labs, which is a grassroots OSM team that maps the locale to improve urban planning, says the report. If this piece of news is to be believed then on the first day itself, 2,182 OSM mappers had made about 58,250 edits to highways and 91,850 to buildings. In the next couple of hours as data sources started pouring in, the focus was shifted to mapping mountainous areas and making population maps. However, OSM data is just one of four key sources the UK and US Red Cross teams rely imagery from. The list also includes GIS-compatible data from GADM (a spatial database of the world’s administrative areas), Natural Earth and the UN Office for the Coordination of Humanitarian Affairs, states the report. On the second day, DigitalGlobe’s WorldView-3 data was uploaded to the satellite company’s crowdsourcing platform Tomnod. The report states that till then 4,534 volunteers had already ‘analysed 14,700 km2 worth of imagery, made 21,975 tags of 3,128 damaged buildings, 1,191 locales of major destruction and 1,129 damaged roads’. Satellite data gradually becomes vital for the relief effort, and is combined with all details and information coming on social media and news outlets. The report also points out that besides the above mentioned teams and groups, several data sources and contributors keep joining in the digital mapping effort.