Integrated Distributed GIS Approach for Earthquake ... - Springer Link

Integrated Distributed GIS Approach for Earthquake Disaster Modeling and Visualization Rifaat Abdalla and Vincent Tao GeoICT Lab, Center for Research in Earth and Space Science, York University, Toronto, Ontario, Canada, M3J 1L1. E-mail: (tao)[email protected]

Abstract In November 2002 a simulated earthquake damage assessment scenario for the Greater Vancouver Region was visualized using GeoServNet. GeoServNet is web-based GIS software developed by York University GeoICT Lab with unique functionality of online 3D visualization and 3D fly. We tested our software in an earthquake simulation exercise that included a simulated Shakemap. Shakemaps are representations of ground motions recorded and extrapolated from knowledge of surface soil conditions. The Geological Survey of Canada is considering applying this technique to Canadian cities at risk. GeoServNet has been used for the demonstration of the utility of Shakemaps and how it could be used in an emergency response scenario. The constructed visual scenarios and information databases is crucial for the purpose of Disaster Management and Emergency Response. Most of currently available tools that are used for disaster management are focusing on the temporal component of the four phases of disaster management leaving an obvious gap in dealing with the spatial element particularly in visualizing disaster and emergency information. This study was conducted as a part of a federal project funded by the former Canadian Office of Critical Infrastructure Protection and Emergency Preparedness (OCIPEP), recently known as the Ministry of Public Safety and Emergency Preparedness (PSEPC). In this study, federal, regional and local authorities along with industry and academic research institutions together coordinated information exchange in a collaborative manner. Results obtained from this project showed that visualization of earthquake disaster scenario was effective and near real time using GeoServNet.

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Rifaat Abdalla and Vincent Tao

1 Introduction PSEPC represents the federal government along with British Colombia Emergency Communications Center (ECOMM) representing the provincial level, York GeoICT Lab, representing the academia and two companies represent the private sector, all collaborated together in developing a pilot information visualization system under the Natural Hazards Action Plan. The information structure developed emphasized on the improvement of the efficiency and effectiveness of managing the four phases of natural disasters. i.e. mitigation, preparedness, response and recovery. The primary purpose of his collaborative effort was to further enhance visualization techniques of Geospatial data for emergency managers. As well as to allow researchers of the collaborating institutions to identify issues associate with the management of data and the infrastructure required. The focus was on a 2D/3D visualization tool that incorporates open standards, wide area access and interoperability for integrating multi-scale Geospatial data. As the global concern of natural disasters is growing, many researchers have tried to come up with variety of solutions for the question of providing efficient and advanced information system that can handle multiple events with the aid of geographic information systems. The ease of using web based GIS for desktop applications was clearly examined by (G. BERZ, LOSTER et al. 2001), they were able to produce multi-layer GIS database that has incorporated multiple hazards. GIS applications in Disaster Management have always tried to support the concept of all hazards modeling. Hazard is often understood as a quantity that relates the occurrence/frequency and intensity of an event to a specific time interval and so is usually expressed in terms of a probability. The hazard information has three essential components – intensity, frequency and reference period.(G. BERZ, LOSTER et al. 2001). Based on hazards and disasters widely accepted definitions, Geospatial data are important for managing all the four phases of disasters and emergencies. Geospatial data include images, vector files and location information. Due to the advance and diversity in technology, Geospatial data consists of many formats and representations. To combine these data and form meaningful information products can be a labour intensive and complicated operation. The presentation of the information products to the emergency responders in the way that the embedded information can be easily digested and understood is still a research topic. If emergency responders were given easy access to basic registers of population, building, tenement and property information, and state-of-the-art tools for risk assessment in

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form of GIS data models, this will certainly ease the processes of disaster management. Many basic infrastructure layers were integrated by (Heino and Kakko, 1998) for producing visual risk models. The application of GIS for hazards and disasters mapping and visualizations is well known and understood. Beginning in the mid-twentieth century, when the use of aerial photography became widespread, triggered by many more earthquakes in a wider variety of environments. Since the 1980s many researchers used combination of GIS and for seismic microzonation studies to assess the likely effects of earthquakes on urban built on unconsolidated sediments. (Jensen 2000). Results obtained from different exercises, including those obtained by Keefer, 2002 have demonstrated that Geospatial data are important for managing earthquake disasters in all the four phases. The interoperability of Web-GIS is of great benefit to decision makers in the filed of emergency management, since it will allow them to access and visualize the same data at the same time.

2 Methodology To provide a relative context to 2D/3D visualization for disasters and emergency situations scenario based enhanced disaster management and risk assessment modeling was applied. With the help of supporting datasets and a mocked storyline, three presentations were conducted to gather more definitive understanding of the user needs in visualization of emergency information. The adopted approach was as following: 2.1 Scenario and Data Preparation To stimulate discussion on the effectiveness of the visualization tool within the context of emergency response, scenarios were developed for the presentations. The first presentation was during the City of Vancouver emergency exercise at the E-COMM Center and the next presentation was at the Center for Research in Earth and Space Technology (CRESTech) in Toronto. Contents from the last presentation were used for the OCIPEP demonstration. The scenario for the E-COMM center focused on utilizing vector spatial data and remote sensing imagery to associate with a fictitious subduction earthquake occurring in the Strait of Georgia. Included in the scenarios were demonstrations of an Earth Shake Map to visualize the intensity of the earthquake.

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Fig. 1. Scenario event locations

2.2 Storyline The mock storyline for the earthquakes used focused on a seduction earthquake occurs in the Strait of Georgia, an earth Shakemap containing MMI and PGA was used. Shakemaps are representations of ground motions recorded and extrapolated from knowledge of surface soil conditions. Shakemaps show the 2D map of the event location, color coded based on the magnitude of the earthquake. The area around the epicenter which has high magnitude is colored in Red with gradual color dilution away from this region. The location of the study area is shown in Figure [1]. Referencing information such as population, roads and other infrastructure are then overlaid in 2D. 2D reference information such as roads, water, and population are critical in damage assessment studies, from both critical infrastructure perspective as well as humans concentration. Manual animation of the topography is done to show the intensity correlating to slope areas. The advantage of 3D visualization lies in the way we see the information and have our own perception towards the fact of what we are exactly looking at, and whether it is symbolic conceptual or semi real world as in


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3D perspective display. Many researchers have recognized that the advantage of 3D lies in the way we see the information. 3D display simulates and enhances realizing the spatial content of the real world. We live in a 3D world; naturally, we perceive and visualize information in 3D much better. Additional point is that 3D visualization provides additional dimension for decision makers. Decision makers are not always heavily involved with mapping, particularly in Disaster Management. 3D GIS is unique in providing them with close to reality models, thus allowing them to more quickly recognize and understand changes in elevation, pattern and features. GeoServNet we demo here is just a beginning, the research and development in the filed of 3D Internet GIS is rapidly evolving. Constructing visual damage assessment model involved many process from desktop (1) data preprocessing and setting visualization parameters to (2) building web-based visualization model using GeoServNet. The first part involved matching various data sets coordinate systems, data conversion, since all vector layers provided were in 3D format (either polyline z or point z) it was crucial to convert those data sets to 2D shapefiles as initial stage for using GeoServNet. The second stage was setting visualization parameters in terms of layers sequence and colors. This project shows how well to link an earthquake scenario to a web-based 3D GIS together, to come up with integrated damage assessment model. Figure [2] highlight the visual impact that 3D GIS can provide in modeling and visualization. 3D distributed GIS gives a new angle to show the model in both 2D and 3D way, and provides a new protocol to deliver the processed model with the most effective way – Internet. It is just for now. The technologies evolve so fast, and there is a lot of exciting Disaster Management applications needs to be explored.

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Fig. 2. GeoServNet 3D Model of Downtown Vancouver

3 GeoServNet Architecture GeoServNet is a distributed web-based 3D GIS which is being developed by GeoICT Lab in York University. GeoServNet provide an easy and accessible data publishing facility. Through the three modules of GeoServNet, i.e. GSNBulider, GSNAdministrator and GSNPublisher, it was possible to make the visual scenario of Santa Barbara Airport available online. GSNBuilder task is to build data i.e. shapefiles, JPEG Raster and ASCII DEM and configure them to make them ready for using GSNAdministrator. GSNAdministrator job is to register the configured datasets to the server and make them assessable to the publishing model. GSNPublisher mainly perform setting visualization parameters in terms of visual effects i.e. color, line thickness and transparency. The other function of the GSNPublisher is generating the application file that would be linked to the web to make the project available online. GeoServNet is fast. It uses progressive streaming technology and intelligent data transmission strategy, which squeeze each drop of the bandwidth for good use. GeoServNet is platform independent. It is designed and implemented using java and java 3D technology, and can be deployed easily in any machine. GeoServNet is interoperable. GeoServNet follow


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OGC standards and has been proved compatible with OGC Web Services. In this project, we use this powerful web-based 3D GIS platform to present a whole new angle to visualize the mock earthquake damage assessment scenario in both 2D and 3D way over the Internet. Figure [3] shows the system architecture of GeoServNet.

Fig. 3. GeoServNet structure

Geographical information always has a location-based element to it: “the where of information”. And the information is usually presented as a map. Not just a picture of a map, mind you, but information as a map.

4 Importance of Distributed GIS The importance of distributed GIS comes from its accessibility by many users. In disaster management applications, there are many authorities that are involved in planning, decision-making and implementation. Desktop GIS doesn’t provide instant and effective multi-user platform for the same project. This capability is mainly one of the most significant advantages of distributed GIS.

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Distributed or network based computing is extremely required for processing large volume of data. Certainly, disasters may extend to large space, thus, simulating natural disasters may require advanced and great computing capabilities. This is where the strength of distributed computing and systems interoperability came from. Distributed or network-based computing share the computing power of all systems within the network. This distribution is crucial in functionality execution, it also share the different network resources to achieve high performance computing through multiuser interfaces. However, such strength is useless without clear interoperability standards for systems and data. Such standards would make the use of advanced functionalities and computing power a useful tool in disaster management applications, particularly in resources sharing and coordination. The clear application in disaster coordination could be emphasized by analyzing the earthquake model of this study. The volume of geospatial data, municipal database, and provincial data, may exceed the processing capacity of a desktop computer. In the same time, users from different decision-making levels would not be able to access information at the same time. In such case and without GIS interoperability, it wouldn’t be a straightforward task to secure simultaneous data access and processing, this make removing system and data heterogeneity is very useful for disaster management applications. Such applications made GIS interoperability a highly demanded mechanism for disaster management coordination. Another advantage that internet-based GIS doesn’t’ require deep technical background, which make it user friendly for decision makers to use GIS.

5 Results Obtained results from this visualization model have clearly demonstrated that GeoServNet was very efficient in handling multiple scenarios. The flexibility and the ease of using this web-based GIS tool were appreciated by all Disaster Management personnel with limited or no GIS background. Web GIS has provided an easy and accessible mean of communication between the various decision-making levels i.e. local, provincial and federal. GeoServNet customizable interface, shown in Figure [4] below allowed for various basic visualization functions and capabilities. GeoServNet 3D visualization functions enabled more sophisticated analysis operations, including, 3D fly, 3D rendering, critical surface functions, and surface profile analysis


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Fig. 4. GeoServNet Client Interface showing Vancouver Shakemap

6 Conclusions The results obtained from this project have indicated that it is very feasible to integrate various data sources for producing Disaster Management scenarios and models. In particular, data obtained from Canada Centre for Remote Sensing, Statistics Canada, Vancouver City, DMTI Inc., Geological Survey of Canada and the Province of British Columbia was very valuable in this study. The process of compiling and rectifying the entire vector data used for the project into a common projection and geographic extent by was crucial for having effective visual model. GeoServNet functionality in particular the 3D visualization and analysis functions were of great use for visualizing earthquake simulation and damage assessment models.

Acknowledgements Special thanks to Dr. Ko Fung and Patricia Pollock from Earth Science Sector, Natural Resources Canada, Steven McArdle from 4DM Inc. and to Michael Morrow from EMIS Technologies for their for providing valuable suggestions and huge input to this study. Many thanks to Dr. Mauricio Artigilo from Geological Survey of Canada for providing study area Shakemap.

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