In the last several years the number of individuals and organizations connecting to the Internet has increased at a dramatic rate. With an estimated 15 to 30 million users maintaining some form of connection to the Internet as of early 1993, the Internet is now a means of distributing geographic information system (GIS) services, data and education to a vast audience. The suitability of the Internet as a vehicle for distributing GIS-related information improved with the advent of the World Wide Web (WWW) and GUI-based browsers such as Mosaic. This paper describes how San Diego Data Processing Corporation (SDDPC) developed a PC-based multimedia presentation to educate the community about available GIS services, and how SDDPC migrated this application to the WWW. This paper also explores possible future uses of the WWW for the distribution of GIS services.
A primary task of any organization is the clear and effective communication of the benefits it provides to the community it serves. Private organizations have long recognized this and place great importance on the identification and description of services and product offerings to their target markets. In the public sector, as citizens require increasingly customized and efficient services from government organizations, these organizations are confronted not only with the development of the required services, but also with the task of clearly communicating these services to their constituents. As a non-profit corporation owned by the City of San Diego, CA, USA, San Diego Data Processing Corporation (SDDPC) is uniquely positioned to develop information management solutions to meet the dual challenge of development of customized public services and the effective communication of their benefits.
In its strategic plan, SDDPC has identified geographic, visualization, and multimedia technologies as essential to the delivery of decision support systems to government officials and customized, easily accessible services directly to the citizen. Actions taken by SDDPC in these directions include the development and implementation of a multimedia kiosk for citizen access to public information, the application of three-dimensional visualization software to assist the City of San Diego in its successful bid to become the host of the 1996 Republican National Convention, and the development of the Regional Urban Information System (RUIS), a regional geographic information system (GIS) for the San Diego region.
To communicate the potential of GIS and the capabilities of SDDPC as a provider of GIS services, SDDPC developed a multimedia application to educate the public about RUIS. This paper focuses on recent work at SDDPC using the Internet and the World Wide Web (WWW) to deliver this multimedia presentation to a broader audience, and exploring issues related to GIS service and data delivery using the WWW.
To understand how GIS can integrate with multimedia and Internet technologies, it is necessary to understand the capabilities of multimedia and internetworking technologies in the communication of information. It is helpful to assess these capabilities by examining the contributions of each technology to the issues of information presentation, defined as the clear and intuitive communication of the information to the user; content, defined as the information itself, including its currency and modification; and scope, defined as the set of information included in the content, including the ability to extend associations to other relevant sets of information.
Multimedia, integrating text, audio, video, and graphics, has been recognized as a valuable tool for the effective presentation of complex information. Despite this significant benefit, the effectiveness of most multimedia implementations is limited by the static state of their information content and scope. The data presented (content), and the set of information to be communicated (scope) of a multimedia presentation is usually embedded in the design of the system. Revision of content and scope is usually performed infrequently, or not at all, due to the intensiveness of the activity of making design changes or physical modifications to the system (e.g. creating and delivering a new CD-ROM) (Mascha and Seaman, 1994).
The scope of a multimedia presentation is often inflexible due to the difficulty of linking the set of information in the multimedia presentation to information sets external to the designed system (Mascha and Seaman, 1994). The problems of content and scope inflexibility are exacerbated when the multimedia system is duplicated and placed at many sites. These benefits and limitations of current multimedia implementations combine to result in systems that are highly effective in communicating complex information, but often unsupportive of content modification and linking with other relevant sources of information.
In contrast, advances in the development of networked systems now enable centralized repositories of information to be shared, and widely-dispersed information to be associated and related, all in the context of a highly extensible distribution framework. These characteristics of networked systems provide potential solutions to the inflexibility of content and scope previously mentioned. However, though networking advances have provided the infrastructure for addressing these problems, the interfaces enabling human interaction with the information have been limited in their ability to allow users to access and assimilate the large amounts of information now available in networked systems. For example, the common relational query- based interfaces to networked databases require substantial knowledge of the database content and structure (Berra, Chen, Ghafoor, and Little, 1992).
Development of the WWW began at the CERN Laboratory for Particle Physics. Researchers saw the potential of integrating the presentation strengths of multimedia with the flexibility of content and scope enabled by networking information. The WWW design implements the Hypertext Transfer Protocol (HTTP) to enable communication between WWW servers. Information is stored in files using the Hypertext Markup Language (HTML) to represent the document structure. HTML supports the use of multiple media, and allows the creation of hypertext links representing Uniform Resource Locators (URLs) that identify the locations of specific documents on specific WWW servers (Putz, 1994). Client software, such as Mosaic, are used to present HTML documents to the user and to enable the use of hypertext links.
The support of multimedia by the WWW retains the presentation effectiveness of traditional multimedia applications. The use of the Internet as the network infrastructure, and the relative ease with which hypertext links can be created, allows information scope to be easily modified. The location of an information resource on a single WWW server provides a single point of maintenance, allowing content modifications to be made accessible instantly to any site referencing the information source.
As a first step in communicating its GIS services to the community, SDDPC developed a PC- based multimedia application describing the RUIS GIS implementation and the GIS services offered by SDDPC's GIS Services Group. The specific goal of this application was to educate the public about how the RUIS regional GIS for San Diego is assisting the City and County of San Diego to better respond to the public need for more efficient and cost-effective government services.
After identifying the target audience and clarifying the objectives, a team was formed to include designers, writers, graphic artists, and audio, video, and photographic professionals. This team then identified the required data, media, and data sources. A system design, including navigation diagrams, was then developed. To achieve the desired quality, most data sources were developed specifically for the project. A professional photographer photographed various city and county customers using GIS in their daily work, a video crew videotaped testimonials by public officials, and professional voice talent was hired for all audio narration. In addition, a graphic designer was hired to design the required background screen graphics.
A prototype of the application was then developed using IconAuthor (Aimtech, Nashua, NH) multimedia authoring tools and the design was refined based on the prototype. Following the design refinement, video and audio were digitized, and required text files were created. Still photography was developed on 35mm slides, recorded on photo-CD, and then converted to bitmap images using Photostyler (Aldus, Seattle, WA) image processing software. Video was digitized using a Macintosh-based video editing suite, then converted from Quicktime format to Microsoft Video for Windows .AVI format. After linking all final source materials into the prototype, revision to create the final version was performed using Multimedia Toolbook (Asymetrix, Bellevue, WA). After testing, an installation program was developed for distribution and the entire application was transferred to CD-ROM.
To explore the integrated use of multimedia, GIS, and the Internet, SDDPC decided to migrate its PC-based multimedia presentation of RUIS and SDDPC GIS services to the Internet. The primary goal of the initial phase was to provide on the Internet an effective presentation of RUIS and SDDPC's GIS services based on the previously described PC-based multimedia application. Steps required to complete the project included review and revision of the existing application design as required for the WWW, data identification and conversion, hypertext link design and HTML authoring, testing and revision, installation on a server outside the SDDPC Internet firewall, and production testing and product announcement.
As a general observation, the experience of the developers on this project indicates that the issues of design and content quality are key to a successful Internet multimedia application. The relative ease of publishing information on the WWW has led to a proliferation of poorly designed information services. Developers of WWW applications should take great care to design their application using a solid understanding of basic principles of communication, and adherence to the emerging standards of WWW document design. In addition, the hypertext medium of communication provides the potential for new advances in communication techniques that should be explored.
If design issues are not adequately addressed by WWW authors the usefulness of the WWW as a communication medium will be greatly diminished as users find themselves sifting through increasing amounts of unintelligible information. In the case of the SDDPC GIS multimedia application, the investment made in navigation design and high-quality content were transferable to the Internet-based multimedia version of the application.
Specific issues requiring attention in migrating the PC-based multimedia application to the Internet included element file sizes, physical sizing of elements, data format selection, use of format and size indicators, image map implementation, and text-only browser accommodation (Gray and Richard, 1994). Lack of attention to these issues, particularly by developers more accustomed to non-networked multimedia applications, is a primary cause of ineffectiveness in WWW authoring.
Most of the aforementioned issues exist because of the large number of users accessing the Internet through 56-Kbps or slower lines. These line capacity limitations were addressed at SDDPC by redesigning the application to restrict photographic images to approximately one-per- page at an average of 30KB per image. Though the use of JPEG formats, due to compression, would have yielded smaller files, GIF format files were produced due to their wider support by WWW browsers. Since audio and video clips easily saturate narrower bandwidths, much audio and video that existed in the PC-version of the application was eliminated from the WWW- version. A single 263KB .WAV format audio file and a single 1MB .AVI format audio+video file were included in the WWW-version.
Image maps, the ability to define operations specific to the area of a given image clicked on by the user, was seen as an ideal means to demonstrate the GIS concept of attribute data associated with spatial data represented as a map. A hypothetical noise contour map was defined as an image map with links to sample data for each noise zone. A different set of sample data is returned depending on the zone clicked in the noise contour map. This gives the user the experience of the spatial/attribute data link without the resource intensity of using a GIS to demonstrate the concept.
Text-based browsers were accommodated by adding functional ALT tags to replace button images and other icons. Where value was not added by the use of an ALT tag, a null ALT tag was specified. The pages were tested thoroughly using the Lynx text-based browser to verify their usefulness to the text-based browser user.
Guided by a strategic goal of developing information management solutions to provide highly customized and accessible sources of public information, SDDPC is exploring the development of interactive data access services integrating GIS, multimedia, and the WWW. Current SDDPC projects contributing to this effort include the provision of remote access of geographic data to an association of private businesses located throughout the San Diego region, and provision of data navigation tools to browse the extensive collection of geographic data contained in the RUIS GIS. To assess the viability of fulfilling the presentation, content, and scope requirements of these various projects utilizing the WWW, SDDPC developers are prototyping geographic data access services on the WWW.
Implementations of data access can range from simple file transfer of a pre-existing file from a remote server using FTP, to the retrieval of a customized dataset dynamically created by a user interacting with a GUI-based web-browser application. Non-WWW-based FTP file transfer of geographic data has been used by SDDPC for some time now. The implementation of simple file transfer on the WWW, providing functionality identical to non-web FTP but utilizing a WWW browser, is currently implemented for city council dockets, minutes, and city municipal codes on the City of San Diego WWW server (http://www.sannet.gov), developed by SDDPC for the city.
The usefulness of this simple method of data access is significant but limited. Examining this method using the conceptual framework of presentation, content, and scope, this method provides obvious content advantages such as data currency, due to the previously discussed advantages of the single-location information resource concept of networked information. However, in terms of the user's ability to define the scope of the information desired, and the effectiveness of the presentation of the data to the user, this method provides little improvement over the distribution of data via other media such as tape or CD-ROM.
SDDPC has prototyped the use of WWW browser software to communicate with remote server ArcInfo (Esri, Redlands, CA) GIS software as a method of providing a GUI-based method of data retrieval using a user-generated query. The Common Gateway Interface (CGI) is a WWW standard for external programs to communicate with an HTTP server (McCool, 1995). To develop the prototype, SDDPC developers constructed HTML documents using the forms features of HTML to accept user input. CGI-compliant scripts were then written to accept the input, call the ArcInfo GIS software on the server, pass the input to the GIS software to perform actions based on the input, including AML execution, and then return an HTML-formatted page describing the results and displayed by the browser.
Further refinement of this prototype is planned to include the use of the image mapping capabilities of the WWW to provide an interface appropriate to the query of spatial data. A few implementations of an "interactive map" approach have been developed, most notably the Xerox Map Maker developed by Steve Putz at Xerox PARC (Putz, 1993). The usage statistics of the Xerox Map Maker reported 25,000 map image requests per week as of February 1994 (Putz 1994), suggesting that such an interactive spatial data service has potential for significant use.
Issues identified during the prototype include security, resource control, and WWW support of RDBMS access. As a general level of security, SDDPC has implemented a firewall to restrict the access of internal networks by users operating external to these networks on the Internet. A more specific level of security must be constructed prior to implementing an interactive service to avoid compromises of server security by WWW browsers using CGI to run programs on the server.
Resource usage and control is a concern for data access providers choosing the interactive, customized dataset approach to data access. The use of a GIS such as ArcInfo by many users attempting to access data would place significant demands on system resources, and licensing costs and associated issues are considerations in such an implementation. Queued methods of controlling query and retrieval are possible but reduce the interactive value of a service.
Provision of a complete GIS service is anticipated to require a method of accessing tabular data by directly addressing an RDBMS. GSQL provides a forms-based method of assembling SQL queries using Mosaic (Ng, 1993). The specifications for table representation in HTML+ (Raggett, 1994) provide capabilities for displaying tabular data in a row/column format that may be useful for displaying the results of GSQL queries.
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Larry N. Sanford
San Diego Data Processing Corporation
5975 Santa Fe Street
San Diego, CA 92109 USA
Internet: dpclws@mainruis.sannet.gov
Telephone: (619) 581-9754
Fax: (619) 581-9617