A Java-Based Fire Simulation Model for the WWW

Jonathan Mann, GISCA, University of Adelaide, SA 5005, Australia. Phone: +61 88 303 3975 Fax: +61 88 303 3498 email: jemann@gisca.adelaide.edu.au

Dr. Steve Kirkby, GISCA, University of Adelaide, SA 5005, Australia. Phone: +61 88 303 3900 Fax: +61 88 303 3498 email: skirkby@gisca.adelaide.edu.au

Dr. Peter Eklund, Department of Computer Science, University of Adelaide, SA 5005, Australia. Phone: +61 88 303 4483 Fax: +61 88 303 4366 email: peter@cs.adelaide.edu.au

Keywords

World Wide Web, Java, Geographic Information Systems, Fire modelling

Abstract

This paper considers the issue of simulated spatial modelling over a distributed network. A simulation model for determining bushfire spread is developed using the platform independent computer language Java and a suitable distributed systems architecture. The system's architecture allows operators to modify bushfire input parameters as required and run their own simulations. This better conforms to the model of fire behaviours as well as operational requirements. Issues of fire model implementation and simulation using Java over a distributed network are considered in this paper.

Introduction

With the increasing acceptance of the Internet as a communication tool, simulated modeling of spatial phenomena is possible over geographically disparate regions to a broader user base. Given the improvement in accessibility for data stored in spatial databases, modelling techniques need to replicate and present the spatial process in an intuitive manner. This case study uses a bushfire simulation model to prototype a software architecture, using raster Geographic Information System (GIS) data and a fire model, and allowing user interaction with the model via the graphical user interface (GUI).

The application domain is emergency service response management to life-threatening natural disasters. During Australian bushfires, emergency service response is coordinated via a central command agency to a series of distributed field sites. Spatial information describes:

the extent of damage,
proposed direction and projected spread, and
areas under threat.

These are communicated via telephone/radio and faxed text or maps; there are no means to convey digital spatial information to users in the field (apart from providing them with their own stand-alone GIS and DBMS). Platform-dependent, single-user fire simulations have been implemented to be used as tactical aids and as training tools, but are not useful for coordination. This research aims to use an integrated Internet/WWW strategy to distribute information to the appropriate user group, particularly focusing on the implementation of bushfire simulation in an intuitive manner.

Background

This study is part of a larger project concerning Emergency Service Management Response (ESMR). This project has already developed a system for routing in the event of an earthquake. This was implemented as a case study for Okayama City in 1995, in which several likely scenarios were modelled and their effect on the road network noted in terms of shortest paths. The bushfire work is a logical extension for the Australian environment.

FireMaster

FireMaster, a Java applet, represents the first phase of the disaster simulation using the WWW and Internet. GIS data is retrieved from a central server, allowing each user to run their own simulation of fire spread on any Java-capable browser.

The system is designed using object-oriented software engineering principles; the architecture of the system is designed to be modified and extended. The system is divided into three main levels:

The Data level: all data needed by the operations to be performed is loaded into the system from a central server. Results of spatial operations are also stored here, and in future will be passed to other users via the server.
The Operational level: each spatial operation exists here as an object, requiring spatial data to run on and producing new data or modifying existing data.
The User level: the user interface, by which the user can invoke operations, choose the dataset to be operated on, and view the results on a spatial display.

Figure 1 shows the graphical user interface.

Figure 1: GUI for FireMaster

Operations are carried out on each client, rather than the server. This means that a large number of users can use the server at once, by using the client's hardware rather than the server's. This also allows immediate response to requests, rather than the delays associated with CGI interaction.

Another problem dealt with is interacting with already-existing GIS information. This has required recoding in Java to access this data. We are currently working on developing a native code interface to the ArcInfo system for the server. This means the applet GUIs will remain platform-independent.

Conclusion

The WWW provides a communication network that can be exploited for purposes of coordination. The FireMaster application demonstrates a realistic use, for which the simulation, data transfer and front end have already been developed. The benefits of Java have been clearly demonstrated in this project. Dynamic simulation is enacted as a client-side operation, thereby precluding the user from time delays caused by network traffic and a busy server. Using this object-oriented architecture we expect to develop further modules to assist planners during life-threatening disasters.

References

Ian Knight and John Coleman, "A Fire Perimeter Expansion Algorithm Based on Huygen's Wavelet Propagation". Int J Wildland Fire 3(2):73-84, 1993.

Tom Beer, "Bushfire-Control Decision Support Systems". Environment International 17:101-110, 1991.

Hypertext References

HREF1: http://www.gisca.adelaide.edu.au/~jemann/FireMaster.html - The FireMaster Java Applet
HREF2: http://www.gisca.adelaide.edu.au/ - The GISCA home page

Copyright

Jonathan Mann, Steve Kirkby, Peter Eklund ©, 1997. The author assigns to Southern Cross University and other educational and non-profit institutions a non-exclusive licence to use this document for personal use and in courses of instruction provided that the article is used in full and this copyright statement is reproduced. The author also grants a non-exclusive licence to Southern Cross University to publish this document in full on the World Wide Web and on CD-ROM and in printed form with the conference papers, and for the document to be published on mirrors on the World Wide Web. Any other usage is prohibited without the express permission of the author.

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AusWeb97 Third Australian World Wide Web Conference, Southern Cross University, PO Box 157, Lismore NSW 2480, Australia Email: "AusWeb97@scu.edu.au"