![]() At present, flood inundation analysis is based mainly on a seeded region-growing algorithm, which is an inefficient process because it requires excessive recursive computations and it is incapable of processing massive datasets. Shen, Dingtao Rui, Yikang Wang, Jiechen Zhang, Yu Cheng, Liangįlood inundation extent, depth, and duration are important factors affecting flood hazard evaluation. To provide more accurate flood extendįlood inundation extent mapping based on block compressed tracing Based on the intensity of tweets in Jakarta during a flood event we can provide a rough estimate of the flood extent. The strength of this method is that it can easily be extended to other regions and languages. These tweets containing a location reference and a water level are considered to be flood observations. Finally, where encountered, a mention of a length measure is extracted as water depth. We therefore extract location information using mentions of names of neighborhoods and points of interest. Since tweets are not always sent directly from the location of observation, the geotag in the tweets is unreliable. It then removes modified and retweeted messages in order to keep unique tweets only. The data-mining procedure looks for tweets with a mention of 'banjir', the Bahasa Indonesia word for flood. In this study we use tweets from the city of Jakarta, Indonesia, to generate these flood extent maps. Our hypothesis is that based on the large numbers of tweets it is possible to generate real-time flood extent maps. A fair amount of these tweets also contains observations of water depth and location. In the city of Jakarta, Indonesia, the intensity of unique flood related tweets during a flood event, peaked at 8 tweets per second during floods in early 2014. With the rise of social media, we now have a new source of information with large numbers of observations. However, getting accurate real-time or maximum flood extent maps remains difficult. Currently, flood extent maps are derived from a few sources such as satellite images, areal images and post- flooding flood marks. ![]() In the post flood phase, information about the flood extent is needed for damage estimation and calibrating hydrodynamic models. This information is very important for disaster risk reduction management and crisis relief organizations. Real-time flood extent maps based on social mediaĮilander, Dirk van Loenen, Arnejan Roskam, Ruud Wagemaker, Jurjenĭuring a flood event it is often difficult to get accurate information about the flood extent and the people affected.
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