Home Articles Web-Based SVG Map System: Design and Implementation

Web-Based SVG Map System: Design and Implementation

Robert P. Biuk-Aghai


Robert P. Biuk-Aghai
Faculty of Science and Technology
University of Macau
Macau S.A.R., China
Email: [email protected]

Abstract
Systems providing geospatial information are numerous, but often are complex and difficult to use, preventing the more wide-scale utilization of geospatial information. We have designed and implemented a system that is easy to deploy and use, yet provides sophisticated map views. Our Web-Based SVG Map System, besides having traditional map viewing and navigation functions, provides map printing, map exporting into GML and PNG formats, and a simple map editing function. It was built using open standards and open source components, and is centred on Scalable Vector Graphics (SVG) technology. It consists of a relational database backend storing geospatial information, a map server implemented by us using Java servlet technology, and a web-based frontend implemented by us using SVG and JavaScript technology. Through the innovative use of asynchronous JavaScript, data transfer requirements are minimized and system responsiveness is improved. This system has the potential to make geospatial information significantly more accessible to and usable by general users.

1. Introduction
Many organizations world-wide are deploying and using geographic information systems (GIS), providing geospatial information to assist management, planning, and decision making. Utility companies, government departments, and others often possess large amounts of geospatial information in these systems which frequently is vital for their operation. However, geographic information systems are usually complex and require significant amounts of training and expertise to be used effectively. This prevents the wider use of geospatial information within the organization, limiting it to a relatively small group of experts. Managers, planners, and other non-technical end users would have much to gain from greater access to this information.

Web-based interfaces to geospatial information have emerged over the past years as an alternative to using the complex interfaces of geographic information systems [6],[9]. However, web-based interfaces usually suffer from several limitations. Firstly, the map displays are typically of inferior quality when compared to those of a desktop GIS. Secondly, the map displays are static, meaning that they cannot provide other information than what they initially display. Any map interaction such as zooming or getting information on map features (i.e. objects on the map) requires a separate request to the GIS web server, resulting in poor responsiveness as the new map view has to be downloaded from the server. Thirdly, web-based interfaces are almost exclusively for viewing only, disallowing editing of geospatial information. Finally, existing web-based interfaces use proprietary technology and data formats that work only with certain proprietary geographic information systems.

We have developed the Web-Based SVG Map System to overcome all of these limitations. It uses Scalable Vector Graphics (SVG) as the core technology for producing and interacting with all map views. The resulting maps are of high visual quality. Moreover, given the nature of SVG, some map manipulation operations can be performed within the web browser without having to contact the web server to request a new map view. Given the programmatic capabilities of SVG, map editing can be performed through this interface. Finally, our system is based entirely on open standards and open source components and is independent of any existing proprietary GIS. Details of our Web-Based SVG Map System are introduced in the sections that follow.

The remainder of this paper is structured as follows: Section 2 gives a brief overview of SVG technology, the backbone of our system. Section 3 presents our system in more detail, and Section 4 discusses the system’s design and implementation. Finally, conclusions are presented in Section 5.