The Japanese government has kept increasing its investment in disaster prevention since the big earthquake in 2011. Japan SuperMap began to focus on the system development to the GIS field related to disaster prevention and disaster prevention field related to spatial information. It has successfully undertaken several related projects commissioned by the government and national research institutes. Retrieval and prediction monitoring system for flood and dyke breaking inundated areas is another new successful application.
Flood refers to the natural phenomenon of the rapid increase of river water volume and the sharp rise of water level. Japan is one of the countries with frequent floods and other disasters. How to make accurate flood forecasting before the disaster happens is a problem that the Japanese government and non-governmental forces have been thinking about and trying to solve. Therefore, the historical data of rainfall runoff and real-time data of catchment capacity have been accumulated year after year.
Flood will have a great impact on reservoir dams, embankments, etc. It is easy to cause serious damage such as flood overflow, dam break and breaking embankments. If the occurrence of flood and the situation of dam break and dyke break that flood may cause can be predicted, the flood control measures and flood warning can be made as early as possible, and then practical flood control plans can be formulated, so as to greatly reduce the controllable losses when the disaster occurs.
The calculation and analysis of dam-break in flood is a very complicated process. It needs to deduce and simulate based on certain mathematical models according to various calculation factors such as flood arrival time, maximum submerged depth, maximum velocity and submerged duration. At present, many researchers at home and abroad have done a lot of research on the calculation and analysis of flood breaking dike, and summed up many mathematical models. At the same time, flood is closely related to geographic information. The flood analysis, monitoring, prediction, prevention and control will be better and more accurate if all kinds of mathematical models are combined with geographic information. In recent years, with the rapid development of GIS technology, the application of GIS in the field of flood disaster has been deepening, and Japan is also involved.
The following part will introduce the application of flood disaster monitoring in Japan, that is the retrieval and prediction monitoring system for flood and dyke breaking inundated areas. The system is constructed by SuperMap Japan.
This system is mainly divided into: flood-inundated assumption area data management module, flood-inundated assumption area data patrol collection module, tile cutting processing module and inundated area retrieval Web site.
Among them, the data management system and the inundated area Web retrieval system are oriented to system users.
Data management system is mainly provided to background system administrators and users of river management institutions at all levels of central and local governments in Japan. The data used in the system are processed, confirmed, released and managed in the background. The data management system calculates and simulates the imaginary breaking point of rivers according to the corresponding data model, and makes the corresponding thematic map layers according to the grid inundated information of 10m*10m inundation area after breaking embankment. Then, the layers are cut into corresponding size and multi-scale tile data, and the information of the time change of inundation in each grid after breaking the embankment is stored in the database.
The Web retrieval system for Inundated Areas is provided to the common people by the Japanese government. They can browse the information of flood breaking and flooding disasters through real-time inquiries of various clients. It can accurately find flood prediction information at any place in real time, understand the dynamic information of flood, and check the real-time monitoring information of river hydrological monitoring points, so as to response to the possible disaster impact in time.
Data patrol collection module and tile cutting processing module will be embedded in data management and Web retrieval system. According to the settings of river management organizations at all levels, the patrol tool automatically searches the local servers and uploads the result data to the system servers for data reorganization and subsequent processing. The tiles cutting tool mainly uses SuperMap Objects. Net components to make thematic maps of flood submergence depth and to cut tiles.
Data Management Background Control System
It mainly includes the functions of data login, data processing, data confirmation and publication.
Main interface of web retrieval system
The retrieval interface provides the basic operation of routine maps. Users can inquiry parameters such as address, residence, facilities, coordinates and so on, as well as the flood and impact information of the location under the corresponding conditions.
Query of breaking dam point
After searching and querying, the interface will display the assumed breaking points which have influence on the searched location and the control of related functional modules.
Schematic diagram of maximum inundation range at breaking dam point
When choosing a breaking point, users can browse the maximum inundation range of the breaking point.
Thematic map of maximum inundation depth at breaking dam point
The schematic diagram of maximum inundation range at breaking dam point and the Thematic map of maximum inundation depth at breaking dam point can be switched with each other.
Animation play of flood inundation at breaking dam point
Time trend map of flood inundation depth
It displays the Statistical maps of flood inundation depth information, elevation and time information of dynamic change of flood.
Real-time water level information map of hydrological observatory station at breaking dam points
It displays the real-time water level monitoring information of correlated hydrological observation stations near the breaking dam place.
Real-time water level monitoring information of hydrological observatory station at breaking dam points