Preetha Pulusani
Executive Vice President, Intergraph Corporation, Huntsville, AL, USA
[email protected]
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 Now, last year’s road atlas is already out of date.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.
Where do we see it going in the future?
The word wired is a synonym for electronic sophistication. It’s a magazine title. It’s a home network of personal computers, scanners, and printers. It’s the Internet. Tourists even get wired in vacation spots around the world. They can buy time at an Internet café and browse the net, read their mail, or play interactive games.
But at the same time we are marveling at this wired technology, techno-explorers are opening a newer frontier – wireless. Intergraph’s expertise in delivering images of maps, and location-related information makes it a natural in this new frontier. People need location-based information in their offices and at home. And people need it even more when they’re away, tethered only by airwaves. Our communities of techno-explorers and ingenious customers have merged to bring this powerful location-based capability to wireless devices.
Consumers have already been able to receive geospatial information on their PCs at work or at home. And now they can receive location-based information including maps anywhere their wireless device can receive a signal. This allows organizations to distribute their investment and lower the cost per seat even more while at the same time providing more people access to location-based data and services.
Programmers recognize JPEG and CGM as common web formats. Now with GeoMedia Web Enterprise, programmers can add WAP – specifically WML (wireless markup language) and WBMP (wireless bitmap) formats – to their toolboxes. AND, people who know how to program products for the desktop are already well along their way toward programming geospatial information for wireless devices.
Software specialists appreciate that they can use open component architecture to create wireless location-based applications. And wireless customers appreciate that they can use these services wherever they are – at the office working or at the seashore vacationing.
Applications, real user examples
Live data – Technology and democracy came together in South Africa’s 1999 presidential election. Using GeoMedia, officials posted real-time election results to the Web and projected them onto large screens at the election center and on the Internet. Viewers could see up-to-the-moment results combined with other related data by merely clicking on a specific geographic region. International media coverage from CNN and BBC World showed live election updates from this system.
Combined data – To help increase Detroit’s economic development and grow its own business, Detroit Edison turned to GeoMedia. Using the Web, potential customers can view detailed information on demographics, available properties, mass transportation, thoroughfares, and more. Searches may be performed by parcel size, existing structure size, or location. Maps, aerial photography, and detailed property descriptions are also available.
Analytical data – Another integration and analysis implementation employs GeoMedia’s Web capabilities. When Hurricane Floyd threatened the coast of South Carolina, GeoMedia enabled SCDOT officials to survey traffic conditions, road closures, and evacuation routes while tracking the progress of the storm. They analyzed this information and successfully routed 700,000 residents of the South Carolina coast out of harm’s way.
Accessible data – Often people have to go to the data. Now the data can come to the people. Highway officials in offices across a midwestern state can observe the path of a snowstorm, road conditions, and the location of each snowplow crew on their Intranet. They can monitor the effectiveness of various ice and snow clearing methods. They can also publish selected information on their Internet Web site for the general public. Monitors at highway rest stops also display the current road conditions. Applications such as this one exemplify the realization of n-tier architecture. It means that the ultimate number of users is unlimited. And people can access the most up-to-date storm information – for free – at home – on their personal Web access devices.
Advice to the users – benefits of Internet GIS
Triangles are the basis for strong physical structures whether they are the pyramids of Egypt or the Hancock building in Chicago. Triangular constructs are also the stuff of strong virtual structures.
People and tasks
Intergraph introduced the tiered representation of a typical user mix for Geographic Information Systems (GIS). The most sophisticated technical people, the Doers, are experts at capturing data from diverse sources and building a cyber-system. Users of the system analyze the data and use it as a primary decision-making tool. Viewers of GIS data may need a map of a particular subdivision in order to lay (or repair) a water line. They may need to verify the progress of a storm. Viewers are the largest population of people who interface with a GIS.
People/task
Hardware
When it comes to hardware requirements, the Doers require the most sophisticated and expensive computers. Fortunately, they can serve their data to a large community of users and viewers at a strikingly decreasing cost of hardware. Users require an interactive connection to the server, usually in a networked environment. Viewers, however, are rarely networked, and often rely on web or even wireless access. Since the viewers are the largest population of the system, every additional viewer seat lowers the cost of the overall system.
Hardware Requirements
Software and n-tier implementations
GeoMedia’s unique data server technology allows the GIS community to select and connect to a diverse reservoir of software data. The various owners (the Doers) of the GIS data maintain their data in their chosen software. GeoMedia implementations reside in the Business Logic tier. Here GIS objects and business objects access and manipulate data in its native format.
N-tier architecture lowers your administrative cost of client PCs, distributes your GIS investment around the enterprise, and provides scalability for the growth of your system. Each tier is virtual and may represent one or more machines allowing you to distribute the workload, dividing your GIS “business rules” from your database server.
With implementations built on these virtual tiers, people can access and analyze data in ways never before possible. And organizations can create the most economical mix of people, hardware, and software.
Software/N-tier architecture
What to look for in an Internet GIS
The data
- Don’t convert it; don’t translate it.
An Internet GIS should be able to access and manipulate the data in its native format. Data is separated from the business logic and presentation medium, so the ultimate consumer is free to use data without having to worry about its format or logic. - Provide access to different GIS data formats
People need to access to many different GIS data formats at one time. An Internet GIS needs to provide the ability to view data from these different formats and/or projections in one view. - Provide live access
Live access means on-the-fly transformation from different coordinate systems, projections, and datums. It also means the ability to work with real-time data (traffic volumes, temporary route blockages, water/tidal levels, current service vehicle locations, and more). - Combine Raster and Vector data
Raster and vector should both be integrated in the same map. And they both should be queryable. That allows the user to select and “swap out” raster backdrops in the map.
The client
Clients with nothing more than an Internet browser on their machine should have access to advanced spatial and network analytical capabilites.
- Perform real-time GIS analysis.
For example, the user can analyze vector features over a raster of soils and then replace the soil raster with a vegetation raster without regenerating the entire map. - The smart map itself should be programmable
The user should be able to manipulate the map presentation with client-side scripting - Accept client-side data
Data supplied by the client side (either as points read in or as a click-on in the map) should be translated into geometry. This geometry can be displayed as a feature object, used for spatial analysis, and even stored as data in a server-side database. - Provide application intelligence
The user can navigate the map (pan, zoom, re-center, and re-project) without compensating for losing the pixel-to-point relationship that is required with static graphics to make them appear to be interactive graphics. - i> Provide Network routing
Typical routing capabilities include point-to-point-point routing, proximity analysis, allocation area (isoline) analysis, and dynamic segmentation. Dynamic segmentation locates a specific point(s) along a sparsely attributed linear element AND associates attribution from another data source (even if this source does not contain spatial data — this includes some spreadsheet applications). - Display attribute data
Display extracted data from any of the data sources on-the-fly as graphics text in the map. This means that the application can create dynamic labels and text features in the map WITHOUT having to create and store graphic text features.
The programming
- Look for OLE/COM
Internet GIS systems benefit greatly from re-usable components within an OLE/COM programming environment. Thus, custom applications can easily be built using industry-standard tools, and you are able to take advantage of Microsoft tools for scalability and load balancing. - You can integrate COM objects with other objects on the server side. For example, take the data from a filtered record set and output it to spreadsheet and charting objects. Or, conversely, input data (such as point coordinates) from a spreadsheet, text file, and so forth, and project them as geometry in the map.
Summary
Openness of data is the key to making the Internet a truly useful environment for sharing information. It benefits both the providers and the consumers of data.
As technology advances and communication rates increase, we expect to see thin clients becoming more powerful. These client seats will be supplied with data from a variety of servers. Being able to roam the Web to search for data and seamlessly incorporate it into a map created from other sources was – until now – an unachievable dream. Today it is an attainable reality.
Being able to permit anyone to interrogate a public database is today’s expectation for Internet sites. Tomorrow, the expectation will be much more interaction with the database by the thin clients.
The broad use of fast, up-to-date, reliable maps on the web will drive this industry to provide a continually improving quality of information. Exceptional new tools will not only improve the quality of communication; they will dramatically improve the quality of decision-making throughout the enterprise.
