Touring Hong Kong via the WWW

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Abstract

In this paper, we present our design of a GIS (Geographic Information System) to provide tourist information to visitors via the WWW. The system can help a tourist, even when he is not in Hong Kong, to find information about routes, buildings, underground railways and train stations. Further, the GIS also allows a tourist to interact with the displayed map by zooming, scrolling, panning, finding out a walking path between two locations with a time estimate, and linking to other WWW locations of tourist hotspots in Hong Kong.

Introduction

Geographic Information Systems (GISs) are computer systems that combine mapping and database management systems for storing, manipulating and analyzing large volumes of spatial and non-spatial data. Example uses of such systems are forecasting in potential market areas, risks analysis, resource management and urban planning. However, at present, many users and developers are limited to local accesses of a GIS. Only recently, the use of GISs via the WWW (World Wide Web) on the Internet is appearing, such as the Virtual Tourist [1], and the TIGER Mapping Service [2]. Nevertheless, most of them still have some limitations as followed:

  • 1.

    They are stateless interface programs that do not remember how a user interacted with the program in the past.

  • 2.

    Only simple interactions, such as single point clickings and text data input, are supported.

  • 3.

    When maps are updated, new HTML documents are generated and downloaded. Hence, it produces higher network traffic and many redundant cache pages.

Thus, there is a need to develop a better Internet gateway which can provide remote users with visual querying of GIS data and allow them to manipulate a map just as in a local GIS. Amongst the many systems available on the WWW, we have selected two of them, the Virtual Boston [4]and Cool Java Map [3]to study further.

The Virtual Boston is a geographic information system developed by Edward Wang. He had built an interactive map of Boston, New York and Lowell. The system supports map navigation and zooming. When a user clicks on a blue label (which links to a uniform resource locator, or URL) on a map, it will start browsing a new WWW location. It also has the function of finding a location by performing a keyword search. However, when we scroll a displayed map, the time to refresh it is obviously long as there is always a need to transfer more data from the server. Further, the zooming feature is limited to the labels provided by the system and a user cannot define his own region.

The Cool Java Map is a geographic information system developed by Andy Wick. It can display different regions of the world, such as the United States, Washington DC, Blacksburg VC and World View. It has similar functions as those in Virtual Boston plus the option of allowing a user to add more URLs. A unique feature of the system is the display of an overview of the world. Through the overview, a user can select different regions of interest for better display detail. However, it has the same display problem as in the Virtual Boston system when a map is refreshed.

After thoroughly reviewing the two systems, we observe that there is still much room for improvement. For example, the zooming functions of both systems do not allow a user to select a rectangular region for zooming. The panning function is slow when we try to move the map around. In a simple test run, we observed that every panning request took about 30 seconds on average to redraw the map.

In our work, we are currently focused on the data retrieval part for map manipulations. In addition to the common features, such as map displaying and zooming, we decide to include new features for a WWW GIS as followed.

  • Showing the location legend when there is need

  • Displayed in two languages: English and Chinese

  • Human-like voice audioclip for the map description

  • Progressive data transfer

  • Walking path searching

The above requirements can be partially satisfied with form processing, imagemaps, and CGI interfaces [5]in a common WWW environment. However, the support of graphical interactions is weak in the current HTML 2.0 specification [6]and even the new HTML 3.0 specification. Therefore we have selected Java [7]as the development platform to develop a map query application named HKMap.

Section snippets

The HKMap system

There are a number of design considerations in the development of the HKMap system. Initially, we want to have a good data structure to store and to index the spatial data for fast query performance. It is also important to consider how we can reduce the amount of data transfer on the network so as to prevent redundancy and inefficiency. For the map data that we acquired, most spatial objects are represented as polygons. This creates a number of problems when we try to implement some of our

HKmap interface design

When the HKMap system is invoked, it appears in a WWW browser as in Fig. 3. At the top of window, there is a menu bar which a user can perform most of the system functions. At the left hand side, there is a map window which shows the current view of a map. At the right hand side, there are four sub-windows. The first sub-window displays a complete map. In the current setup, it shows the Tsim Sha Tsui district of Hong Kong. Within the map, there is a rectangular box which corresponds to a

HKMap implementation

In our initial prototype of the HKMap system, we have selected the Tsim Sha Tsui District, which is a popular tourist area in Hong Kong, as the basic mapping region. The digital map data is obtained from the Lands Department of the Hong Kong Government. There are 22 map sheets to cover all the regions in Hong Kong and Tsim Sha Tsui is one of the highest populated districts. In addition to the spatial information such as roads, buildings, train stations and railways which are available in the

Conclusions

There is a need to develop an interactive and graphical WWW gateway that supports remote users to perform spatial queries of GIS data. The HKMap system has demonstrated the possible improvement on interactions by using the Java Language. In the system, we have developed a set of basic interaction features, such as zooming, scrolling or panning, changing the displayed color, finding location, and linking to the outside world. Other advanced features such as building recognition, playing audio

Vincent Ng received the B.Sc. degree in mathematics and computing science from the Simon Fraser University, Canada in 1982. He later studied in the University of Waterloo, Canada, and received his M. Math. degree there in 1986. In 1994, he received his Ph.D. degree from Simon Fraser University. Since 1994, he has been an assistant professor in the Hong Kong Polytechnic University. His research interests include spatial databases, data mining and medical imaging.
Stephen Chi Fai Chan received a

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Cited by (3)

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    2003, Computer Communications
    Citation Excerpt :

    Various sub-disciplines in the computer science arena have similarly carried out experiments and developed specialist applications with the tourist in mind. Researchers in areas as diverse as Geographical Information Systems (GIS) [1], robotics [2] and Internet related technologies [3] have found tourists a useful target group. Of particular interest are mobile or roaming tourists.

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Vincent Ng received the B.Sc. degree in mathematics and computing science from the Simon Fraser University, Canada in 1982. He later studied in the University of Waterloo, Canada, and received his M. Math. degree there in 1986. In 1994, he received his Ph.D. degree from Simon Fraser University. Since 1994, he has been an assistant professor in the Hong Kong Polytechnic University. His research interests include spatial databases, data mining and medical imaging.
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Stephen Chi Fai Chan received a B.Sc. in electrical engineering from the University of Rochester, an M.Sc. from the University of Wisconsin-Madison, and a Ph.D. from the University of Rochester in 1987. He has since worked for a computer graphics company and the National Research Council of Canada before joining the Polytechnic University in 1993, and is currently an associate professor in the Department of Computing. His research interests include geometric modelling, data engineering, computer-integrated manufacturing information systems, and computer-aided learning.
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C.M. Ng received his B.Sc. and D.Phil. degrees from the University of Ulster, United Kingdom in 1987 and 1993 respectively. Prior to joining the Hong Kong Polytechnic University in 1995, he was on faculty in the School of Software Engineering and Information Systems, University of Ulster, where he taught computer and multimedia information systems. Dr. Ng has been engaged with computer graphics research in his doctorate study. He has numerous publications in international journals and conferences. His current research interests include computer graphics and multimedia information systems.
Fergus Tang graduated from Hong Kong Polytechnic University with a BA (Hons) in Computing Studies in 1997. He is interested in Java programming and Internet applications.

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The work of the first author was supported in part by the RGC Grant: 0357/017 and in part by the Polytechnic University Research Grant: 0351/089.

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