MAPBOT: a Web based map information retrieval system
Introduction
Maps are being used increasingly in local, networked and mobile information systems for communicating geographically referenced information. This has become possible because of the now relatively widespread availability of digital map data and developments in geographical information system (GIS) technology. The applications are wide ranging including local government planning, environmental monitoring, market analysis, navigation and public access to information.
Interaction with a digital map is typically based on a cycle of elicitation of user input via menu and dialog boxes, selection of a map areas or features, and return of information, which may in turn induce modification to the map content. The maps themselves are often close replicas of traditional paper map cartography. The approach is to be found in many commercial GIS and is now being reflected in mapping applications on the Internet. Developments in human computer interaction with regard to information retrieval and data visualization raise the question of whether the conventional approach can be improved. Certainly there is a motivation to investigate new approaches, since the current map interface, particularly on the internet, often suffers from poor legibility of symbols and text, unnecessary user actions and inadequate adaptation to user interests.
Recent years have seen a marked interest in agent-oriented technology [3], [4] spanning applications as diverse as information retrieval, user interface design, network management and complex system simulations [8], [5]. An agent is a computational entity which acts on behalf of other entities in an autonomous fashion, performs its actions with some level of pro-activity and/or reactiveness, exhibits some level of the key attributes of learning, cooperation and mobility [1], [7]. The next generation of GIS may be expected to provide user interfaces with intelligent agents to assist users to search, query and operate the system [2], [6]. The use of agents to represent map features is a characteristic of the EU-funded project AGENT [9], which addresses the problem of map generalization, but is not directly concerned with information retrieval or interactivity issues. We present MAPBOT, a multi-agent system for active maps which makes use of software agent technology for Web based map information retrieval. An active map has the following features.
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responds helpfully to direct manipulation of the displayed map symbols.
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exhibits intelligence with regard to knowledge of concepts and context of individual map features and classes of feature.
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guides the user to relevant related information within the map space and within the information space.
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modifies its map symbols, icons and text dynamically to assist in focusing on particular type of information and particular geographical locations.
This active map will be associated with different agents—representing geographical phenomena, capable of communicating with the map user, visualized by symbolic or iconic representations that adapt to the scale and purpose of the map, and knowledgeable of their ontology, their spatial context and the application specific procedures that might be applied to them.
The remainder of this paper is organized as follows. Section 2 compares MAPBOT with related work. Section 3 presents the software architecture of MAPBOT specifying the agent properties, functionalities and interactions of the Maplets that represent individual map features. Section 4 describes the implementation of the MAPBOT prototype system which uses a Java Servlet for Web communications, the Scalable Vector Graphics (SVG) standard for visualization and a simple ontology in combination with a GUI-based ontology editor, to encode the user concepts associated with Maplets. Section 5 gives future work and concludes the paper.
Section snippets
Related work
A major problem in developing query interfaces is how to guide users in what queries they can ask. Users need knowledge of what it is possible to ask in a particular domain. Having to recall the nature of the data within a repository, as well as the query language itself, means that querying and exploration of data will be difficult. Bechhofer [15] describes a mechanism that defines the relationships between concepts in a domain ontology, allowing a user interface to be generated offers a user
Agent attributes in MAPBOT
According to Maes [14], an agent is a system that tries to fulfil a set of goals in a complex, dynamic environment: It can sense the environment through its sensors and act upon it using its actuators. The agent paradigm has been the subject of Artificial Intelligence (AI) Research and it is beginning to spread into information technology and commercial markets. The attributes of agents used in MAPBOT are given below.
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Autonomous: exercises control over its own actions.
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Reactive: responds in a
The implementation of the MAPBOT prototype
A MAPBOT prototype has been implemented in Java. The source dataset used in the prototype is derived from Ordnance Survey Land-Form PANORAMA map sheets. The UIA is implemented as a Java Applet and runs on the client side to interact with a Web user. The SAB is implemented as a Java Servlet using Tomcat 3.2.4 as Servlet engine. The Ontology Repository is implemented as a serialized Java object and sent from the Serlvet to the Applet during system initialization. Each Maplet is implemented as a
Conclusions
Most Web based map interfaces suffer from poor legibility of symbols and text, unnecessary user actions and inadequate adaptation to user interests. MAPBOT, an active map system using software agent technology is presented to solve these problems. A system prototype has been implemented in Java to test the efficiency and effectiveness of the active map. Based on the Ontology Repository definition, the system can dynamically and semantically adapt to a user query request. The visualization using
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