What is Internet GIS?
An eight-year-old child uses her Web page to sell Girl Scout cookies. An engaged couple includes a Web address in their wedding invitations so that people will have access to hotel and reception information, pictures of the happy couple, and their gift wish list. So, the question becomes "What's so special about GIS using the power of the Web?" And the answer is - plenty! This paper presents one GIS vendor's perspective of internet GIS - what it is, what its benefits are to the user community and a view into its future.
GIS stands for Geographic Information Systems, with an emphasis on information. Geographical information always has a location-based element to it … the where of information. And the information is usually presented as a map. Not just a picture of a map, mind you, but information as a map.
I enjoy looking at the beautiful maps drawn by ancient cartographers. At one time, vellum was the perfect medium for their information. Now, last year's road atlas is already out of date. And when a utility crew is wiring a new subdivision, their maps change even as they are being created. When it comes to geographic information, the web is the perfect presentation medium. It can provide current, analytical, multi-source information. At the office … at home … or anywhere your cellular phone can receive a signal.
A brief look back at web publishing
In 1997, Intergraph was one company that introduced GeoMedia WebMap for the expressed purpose of adding real value to GIS databases that already existed. This was a pioneering venture - to publish GIS data on the web as a standard extension to traditional GIS applications.
Unlike web applications at that time, we would dynamically create maps based on the moment-to-moment state of the GIS database. Now providers could distribute real-time data and information both within and outside an enterprise. It proved to be a highly successful method for distributing geographic information.
The traditional standard at the time delivered a GIF image of the geographic data. GIF images are bulky and dumb (they know if a pixel is turned on or off, and what color it is). Quality is only slightly better than an average quality FAX. GeoMedia WebMap delivered highly compressed, intelligent files. (Intelligent images know something about themselves. Their x-y coordinates. Whether this is an interstate highway or a county road. And the length of this particular segment of that road.) Not only were the maps smaller and of higher quality, but now maps were intelligent as well. At Intergraph, we call these SmartMaps.
We chose WindowsNT Server as the operating system. It provided enhanced operation and rapid implementation during the dramatic early growth of the Internet. This surge to the web surprised even the IT professionals.
At the same time, providers of information and customers of information were becoming more sophisticated. Providers saw both financial benefits and increased good will. Customers saw both current and easy accesses to information. Insomniacs could even see the information they wanted ... at home ... at 3:00 AM. These dual demands for accuracy and access drove the continued development Internet GIS.
What to publish
Enterprises like governments, transportation departments, and utilities maintain volumes of information. Publishing all the contents of these huge quantities of information would be neither cost-effective nor realistic. In addition, information is printed on paper, a fixed medium. It may or may not reflect the true state of the data at any time after publication.
But, it IS realistic AND economical to disseminate selected information on the web.
- Intranets are particularly powerful for distributed, multi-site organizations. Within the protected cyber-walls of an organization, people share selected pieces of data throughout the organization. With updates to the core data immediately published on the web, every facet of the organization has the real information they need, delivered in real time.
- Internets are particularly powerful for
communicating with the public. With their information-store safely
behind a firewall, the enterprise decides what information to
publish beyond the wall. They can publish selected information
about power outages, road repairs, or taxation districts without
publishing sensitive or financial data. They do this by
maintaining an up-to-date subset of their total data on a server
outside the firewall, and using an Internet GIS to publish it to
the world.
What to view
If there's one complaint about the web, it's usually that there is just TOO MUCH information available. People want access to what-they-want, when-they-want-it. And they want to be able to do it without high training costs.
With a sophisticated Internet GIS, people can specify their unique areas of interest and then see the information described in a map. Or, in the reverse, they can click on a map feature or area and see selected database information about that particular map item. They get a very easy way to navigate through large quantities of information. Using very simple user interfaces. Viewing simple, dynamically- constructed maps that reflect the current state of the information.
Publishing diverse GIS data
Many viewers need information that combines data from different sources on a single map. For instance, they would like to retrieve data from a utility database and a land-use database, and then combine them with a demographic data set and display them together in a map.
In addition, to make this information truly useful, the publisher needs to deliver intelligent map features. That means that each feature in the map needs to have sufficient intelligence to know which database to search for its attribute information. This permits an end-user to retrieve data about any "hot spotted" feature on the fly.
Viewers also need to see maps that integrate data from multiple data formats, possibly stored in different map projections. A set of interface components known as Geographic Data Objects (GDO) was developed based on the fundamental concepts and emerging standards of the Open GIS Consortium. These GDO's allow data to be retrieved in a completely standardized way from virtually any GIS database without pre-translation and combined into a single, seamless map view of the database.
In the same way that HTML links text data on the Web, Internet GIS can link items like aerial and satellite images, photos, video, or audio. By clicking on hot-spots in a drawing, end-users can access the related text, graphics, video, or other information you want to publish.
Finally, viewers have asked for raster backdrops to their maps. This additional visual information expands and enhances the viewers' understanding of the map display.
Our ability to fulfill these varied and challenging requests from the mapping community has truly brought GIS into the mainstream of information technology. No longer an isolated piece of the enterprise, GIS is now an integral piece of the enterprise's most valuable asset, its information.