Tweets turned into flood maps that could help save lives
By Megan Rowling
BARCELONA (Thomson Reuters Foundation) - Spontaneous tweets about major floods are being turned into a mapping tool that could be used by emergency services and disaster response teams to save lives and provide aid, Dutch researchers said.
When a crisis strikes, people increasingly find out about it from social media, as individuals and groups take to the internet to spread the word.
After the Indonesian capital Jakarta was hit by floods this February, related tweets peaked at almost 900 a minute, with a significant number including information about location and water depth, according to a joint study by two Dutch organizations, Deltares and Floodtags.
The team then analyzed the thousands of tweets - and others from similar flooding a year earlier - to derive a method for creating real-time flood maps based on Twitter messages, statistics and data on land elevation and water motion.
"This method is really fast," Deltares flood expert Dirk Eilander told the Thomson Reuters Foundation. "It can produce a map within around a minute of messages being posted."
Jakarta has some gauges that measure water levels, but there is no network that can give an overview of flooding street by street. Many tweets, on the other hand, contained detailed information about how many centimeters deep the water was at particular spots, Eilander said.
Because observations by ordinary people tend to be rough estimates, the data need to be filtered, enriched, validated and transformed into easily interpretable maps that can be used by disaster managers.
When the researchers compared their results with photographs of the Jakarta floods at more than 100 points, they found they had modeled the floods correctly in around two thirds of them and in three quarters of districts. Continued...