And Compilation of Digital Atlas of Natural Disasters in China*

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1 TP TP Geographic Information Sciences Vol.6,No.2,December PTUnderstanding of Natural Disaster Databases Design And Compilation of Digital Atlas of Natural Disasters in China* Shi Peijun, Wang Jing ai, Yang Mingchuan, Chen Jin, Pan Yaozhong, Wang Ping, Fang Weihua, Zhou Wuguang, Wan Ying, Yuan Yi, Xu xia Key Laboratory of Environmental Change and Natural Disaster, The Ministry of Education of China. School of Resources and Environmental Science, Beijing Normal University. Beijing, Abstract:Design of disaster databases is classified to 3 types: the statistics-orientated, the system-orientated and the process-orientated. The interaction of information technology, design of disaster database and disaster science is discussed. An interactive and analytic multimedia atlas system, Digital Atlas of Natural Disasters in China, is developed to distribute the data and the scientific results of natural disaster study in China. The atlas system, in which functions of different media in human cognition and communication process are considered carefully, integrates the basic disaster information, flood disaster and earthquake disaster. Keywords:database digital atlas natural disaster in China 1. Introduction China is one of the most disastrous countries. The economic losses and its proportion to GDP of flood, drought, earthquake and sandstorm keep on increasing in recent years. The direct economic loss of natural disasters was 77.9 billion Yuan (about $9.4 billion) in 1991 and rose to billion Yuan (about $27.5 billion) in Natural disaster database is an essential base to the understanding of disaster regionalization, disaster system, and mechanism of disaster. The progress of natural disaster database design can stimulate the progress of disaster science, and vice versa. In order to publish and spread the data and scientific results of disaster study in china, Digital Atlas of Natural Disasters in China, a GIS-based interactive and analytical multimedia digital atlas system, was developed. 2. Disaster Database Design The design of natural disaster databases experienced 3 phases, evolving from statistics-orientated phase to system-orientated phase and then to mechanism-orientated phase. The target of disaster design in each phase is different. The statistics-orientated database mainly focuses on spatial regionalization or spatial pattern of disasters. The system-orientated database is constructed with the development and under the guide of disaster system theory (Shi Peijun, 1991, 1996). The Process-orientated databases mainly concentrate on the mechanism of disasters. The progress of disaster science is reflected by the evolvement of disaster database design. Today, these databases have been the cornerstone of Digital Atlas of Natural Disasters in China. 2.1 Statistics-orientated disaster database The theory of disaster system has not been put forward yet in the early period of natural disaster research and case study of disasters is developing. The database constructed in this period mainly aims at disaster statistic and losses. Most databases are created under the support of dbase or FoxBase in Dos system (Chenjin, 1992). Statistics-orientated disaster databases often use attributes of disasters in core monitoring areas, taking administrative boundary as spatial unit. The geographical distribution of natural disasters can be well reflected in these databases. The representative databases in this phase are Agricultural disasters in Hunan Province, Agricultural and 1 PT* Supported by National Science Foundation of China( ) and Key Project of Ministry of Education, China 140

2 Shi et al: National Disaster Database Design P pastoral disasters in Inner Mongolia Autonomous Region, Natural disasters of each province in China(Tab1)Wang Ping, et al, 1999, Pan Yaozhong, et al, 1997, Wang Jing ai, et al,1995). 2.2 System-orientated disaster database With the progress of natural disaster research, the theory of disaster system was put forward. According to the theory, a disaster system comprises 3 components: hazard system, hazard-formed environment and human system. The relations between components and their effects on disaster losses were studied and articulated (Shi Peijun, 1991, 1996). Under the guide of this theory, the target of natural disaster databases is to record the attributes of hazard-formed environment, hazards and human system. The representative system-orientated databases are Comprehensive agricultural disasters in Hunan Province, Comprehensive agricultural disasters in Hunan Province and Historical flood disaster in 7 main drainage basins of China (Tab 1). The supporting software includes FoxPro for Windows, Visual FoxPro, Sybase, SQL server and so on. Large area natural disaster insurance in Hunan Province integrated the remote sensing data, landuse map and digital elevation model (DEM). Basic disaster units (disaster-homogeneous area) were created by layer overlay. The basic disaster units realized the integration of agriculture hazard-formed environment, human system and disaster loss. However, the application of the databases is often constrained to cropland area and insufficient in description of hazards. Historical flood disaster in 7 main drainage basins in China covers the 176 years from 1736 to 1911, with administrative boundary of county as spatial unit (Fang Weihua, et al, 1998). The spatial patterns of historical flood in different periods are reconstructed with geostatistics method. Flood risk in Yangtze River Drainage Basin is also assessed according to the long and complete flood disaster loss series. However, due to the limitation of accuracy of historical documents, the mechanism of flood disaster in this period remains unresolved. Comprehensive agricultural disasters in Hunan Province (Wang Ping et al,1999) adds disaster effect factor based on the former research. The basic units of hazard-formed environment and human system are built up by overlaying the geomorphology data with landuse data, and then, by using the celling method. The disaster losses are assigned to basic units from administrative county, according to the transferring weights (Fig1). This method covers the entire disaster system, so it provides a method of comprehensive representation of hazard-formed environment, hazard, human system, and disaster losses in the disaster system. But how to define the transferring weights for the administrative county remains a question. Fig. 1(a) Generation of the Blocks of Natural Disaster Basic Units 141

3 Geographic Information Sciences Vol.6,No.2,December 2000 There are two basic units, and transferring weights are 2 and 5 respectively(a); There are two administrative. units, loss data of natural disaster are 10 and 40 respectively(b). Step 1: Generate the even cells coverd all of the basic units; Step 2: Assign each cell the weight from basic units which contained this cell(c); Step 3: Summarize the weights of each admin. units from cells it contained(d). Step 4: For each cell, calculate its loss number from the ratio of its total loss number(e); Step 5: For each basic units, summarize its loss number based on the cell loss data it contained(f). Fig. 1(b): Attribute Data Transferring in Space A,B and C represents 3 polygons, and p1,p2,p3,p4 are length of arcs consisting of A,B and C, therefore: PBAB=p1+p2, P BB=p2+p3+p4, PBCB=p4 PBABB=p1+p3+p4,PBACB=p1+p2+p4, P BCB=p2+p3 PBAB+P BB PBABB=p2*2, PBAB+PBCB PBACB=0, P BB+PBCB P BCB=p4 * 2 Based on this, the SNI(Spatial Neighboring Index) could be calculated as these: NBABB=Max(p2*2/(p1+p2)/2,p2*2/(p2+p3+p4)/2) (0,1) Polygon A is neighbored with Polygon B NBACB=Max(0,0)=0 Polygon A is separated from Polygon C N BCB=Max(p4*2/p4/2,p4*2/(p2+p3+p4)/2)=1 Polygon B is embedded with Polygon C Fig. 1(c) Three kinds of neighboring indices under the different spatial relationships 2.3 Process-orientated disaster database With the progress of the theory of disaster system, the mechanism of natural disaster becomes the key issue of disaster research. However, the above statistics-orientated and system-orientated databases can neither reflect the development and the formation of natural disasters, nor explain the process of natural disasters and hence can not explain many disaster cases. Therefore, the process-orientated disaster databases, emphasizing on the developing process of natural disasters, record the whole process of each disaster case. It is more complicated than the above 2 types of databases. A process-orientated database usually comprises several disaster cases, which forms a holistic 142

4 Shi et al: National Disaster Database Design P description of the disaster process. In order to reflect the complicated relations between cases, Visual FoxPro, Sybase and SQL server are often chosen as the supporting software flood disaster in China and Precipitation-runoff-flood in Shenzhen city are process-orientated databases (Tab 1). Tab 1 types of disaster database design Type Contents Completing Time Supporting software Statistics Agricultural and pastoral disasters in Inner 1991 dbase, FoxBase Mongolia Autonomous Region Agricultural disasters in Hunan Province 1993 Dos System FoxPro for Windows Natural disaster losses in rural area of China 1994 Windows System Indemnity cases of natural disaster insurance in 1995 Hunan Province Historical flood and drought disasters 1996 Natural disasters of each province in China 1995 System Agricultural disasters in Shanxi Province 1994 Visual FoxPro Large area natural disaster insurance in Hunan 1997 Sybase, SQL server Province GIS System Emergency management for natural disaster 1998 (Arc/Info; Info) insurance Comprehensive agricultural disasters in Hunan 1999 Province Historical flood disaster in 7 main drainage basins 1999 of China Process 1998 flood in China 1999 Sybase, SQL server Precipitation-runoff-flood in Shenzhen City 2000 GIS System Disaster database Hazard Hazard-formed environment Human system Disaster case Mechanism Formation Disaster science Driving force Disaster dynamic Disaster warning Disaster loss Process-orientated database System-orientated database Statistics-orientated database Information technology Fig.2 Interaction among the progress of IT, database design and disaster science 3. Compilation of Digital Atlas of Natural Disasters in China Digital Atlas of Natural Disasters in China integrates the technologies of multimedia and visualization of spatial data. It is not a view-only atlas, but an interactive and analytic tool for presenting, analyzing and understanding the disasters in China. Unlike conventional static and isolating representations of disaster information, all the maps in the atlas are created directly from existing databases, and some maps are linked to text explanation, pictures, satellite images, sound or videos of disasters. Functions of different media in human cognition and communication process have been considered carefully in the atlas. Users can find any 143

5 Geographic Information Sciences Vol.6,No.2,December 2000 map from a file browser or by a Structural Query Language (SQL) expression that supports fuzzy match. 3.1 Contents of atlas There are totally 571 maps and 104 tables in the atlas, which are divided into 3 parts: the background disaster information (preface), the flood disaster and the earthquake disaster. The preface comprises 34 maps (19 maps of hazard-formed environment and 15 maps of disasters). The atlas contains 341 maps and 104 tables of flood disaster, of which 77 maps and 24 tables of cover the whole China, and 48 maps and 58 tables cover different drainage basins, and 216 maps and tables cover most of the provinces in China. In the part of earthquake, there are 196 maps with 71 maps of earthquakes in China and 29 maps of region-scale and 96 maps of earthquake cases. 3.2 Workflow of atlas File browser SQL query (fuzzy search) Open file Multimedia: text, image,sound,animation, video Datasets Vector Layers(point, line, polygon) linking Find object, Attribute Info Query Layer1 Table 1 Field1,Field2 Layer2 Layern Datasets Table 2 Field1,Field2 Table n Field1,Field2 Generation(1): Thematic map control (add, remove,modify,reset) Generation(2): Layer Control thematic map type: range, bar pie, dot density, graduated, independent value Legend: title, style, position Style of point, line, polygon and area; layer order, label and visible property Fig.3 Workflow of digital atlas of natural disasters in China 3.3 cartography generation, symbol system and Information communication The principal question of cartography integration about digital atlas is how to define the cartographic basic units, also known as the basic spatial units, which store large amounts of natural disaster data. The scale of spatial unit determines the spatial resolution or precision of natural disaster information. Digital atlas of natural disasters in China uses the administrative county as the basic cartographic unit. There are 2375 counties in China, which reflect basic economic and disaster loss units in China. There are 2 major map generation methods in the atlas system. The first one realizes the map generation by classifying disaster index. In the process of classification, pre-defined statistical method and customized method are available to reflect the geographical principles of disasters. For example, the 144

6 Shi et al: National Disaster Database Design P frequency and risk generation in map should accord with disaster spatial and temporal principles. The degree of disaster should also be reflected and is often divided to several levels, such as heavy, medium and light disaster. In general, this method may be implemented in conventional hard-copy maps. The second method is to control and change the properties, such as label, visible and display style, of each layer on different map scale. For example, when users zoom a map to a larger scale, more information, such as more layers or labels may be displayed automatically. However, when zoomed to a smaller scale, the atlas system can hide part of layer or some layers. Therefore, the displaying contents in a map may change with the scale of the map dynamically and automatically. Both map editors and map users may control the way of map generation. Data Source Data Digi-tiz ing Symbol Text Sound Graphics Symbol Anima-ti on Picture Video Tab. 2 Symbol language system of Digital Atlas of Natural Disaster in China Language Language Type Phenomenon of Natural Disaster Controls Grade Graphs Qualitative and quantitative display of District Graphs natural disaster Set Grade Dynamic Chart Overlaying and dynamic display of natural Set Color disaster system Point Symbol Set District renew of natural disaster Set Layer Animation Regional distribution rule of natural disaster Data House Character Table Voice Sound Music Interactive Encoding Graphics Flowchart Pictures Linear Symbol Area Symbol Point Symbol Modular Cartoon AVI Landscape Air Photo Space Image Video segment Hot-link Area Set Layer Switch Control Show in time Show in select Show all along Hotlink Area Set Layer Static layer, and dynamic show (flash,move, appearance, etc) Dynamic process display Dynamic control display (Interactive) Zoom and Roam Set Layer Button control or automatic show Button Control Interface Control Qualitative and quantitative description of natural disaster Live sound of natural disaster s bursting out, such as: flood, fire, rainstorm s sounds, etc Solemn music related with disaster Easiest music used to release mood Mechanism of natural disaster system Statistics of natural disaster Distribution of natural disaster type, and its routine moved away Alert of heavy natural disaster Spatial differentiation analysis of natural disaster Roam of spatial natural disaster Dynamic processing of mechanism of natural disaster Dynamic processing of changes of natural disaster Observation and monitoring of natural disaster Effects of natural disaster Spot condition of natural disaster process Human-PC s interactive operation of analysis with atlas of natural disaster Personalization of analysis with atlas of natural disaster Information communication model of digital atlas of natural disaster in China (Fig.4) is the communication process from map editors to readers, based on system of regional natural disaster and theory of communication of cartography. Compared to conventional map, digital atlas has three major advantages. Thematic maps are generated directly from data sets and are linked with multimedia information. It is an interactive system instead of a view-only system. Cartographers and map-readers may change their roles. -readers may modify maps or generate new maps based on the existing data. It is also an analytical 145

7 Geographic Information Sciences Vol.6,No.2,December 2000 system. Readers may re-analyze the distribution rule of natural disasters, and obtain their own understanding of natural disaster. D=A B Materials and Data 2 Language Digital Atlas Interpretation 3 1 Atlas Editor 2 Cartographers 3 -reader A: Hazard-formed environment B: Hazard C: Human system D: Disaster ---> Information communication of Disaster Interaction between Users and Atlas Fig. 4 Information Communication Model of Digital Atlas of Natural Disaster 4. Conclusion and Discussion The targets of 3 types of natural disaster database: the statistics-orientated, system-orientated and process-orientated databases are different. The evolvement of database design reflects the progress of disaster science. The statistics-orientated databases aim at the study of disaster geography, i.e., the spatial distribution and principle. The system-orientated databases are constructed under the guide of the theory of disaster system. The primary task of the system-orientated databases is to understand the interaction and the relation among hazard, hazard-formed environment, human system and disaster loss. In order to understand the mechanism of disasters, process-orientated databases are constructed. According to our experiences, the information technology not only strengthens the efficiency and ability to analyze data of natural disaster, but also stimulates the science of natural disaster. At the same time, the achievements in natural disaster research call for innovation of IT, which may contribute to a better understanding of natural disaster science. Digital Atlas of Natural Disaster in China, a GIS-based, interactive and analytical multimedia system, is developed. The 3 types of natural disaster databases are integrated into the atlas. The data and scientific results of disasters in China in the atlas are not only valuable for disaster scientists and policy-makers, but also helpful and beneficial for individuals, households and companies. Reference [1] Shi Peijun, Theory and practice of disaster research, Journal of Nanjing University (science edition), Special Issue for Natural Disaster Study, November, 1991, P37-42 [2] Further discussion on theory and practice of disaster research, Journal of Natural Disasters, 1996, 5(4), p6-17 [3] Chen Jin, Study on agriculture disaster in the agricultural-pastoral transect in Inner Mongolia Autonomous Region, Master paper, Beijing Normal University, [4] Wang Jing ai, Shi Peijun, Zhu Li, Construction and application of natural disaster database, Journal of Beijing Normal University (science edition), 1995, 31(1), p [5] Pan Yaozhong, Shi Peijun, Study on basic spatial unit of regional disaster system (1): theory, Journal of Natural Disasters, 1997, 6(4), p1-9 [6] Pan Yaozhong, Shi Peijun, Study on basic spatial unit of regional disaster system (2): application, Journal of Natural Disasters, 1998, 7(1), p

8 Shi et al: National Disaster Database Design P [7] Wang Ping, Review on comprehensive regionalization of natural disaster, Journal of Natural Disasters, 1999, 8(1), p54-60 [8] Fang Weihua, Wang Jing ai, Establishment of historical flood disaster database, Journal of Beijing Normal University (science edition), 1998, 34(2), p [9] Zhou Wuguang, Shi Peijun, Establishment and application of indemnity database of natural disaster insurance, Journal of Natural Disasters, 1999, 7(3), p