The following are examples of DGI application that can be found on the web:
Raw Data Download
This application involves little or no processing but rather is a simple information exchange. A clients browses the servers files just as one would in their own "file manager". The files are arranged and usually cross referenced according to the client's search. The pertinent files are then downloaded in dataset form and manipulated by the client once they are in their own GIS software.
Static Map Display
This is, again, a simple DGI application which involves the display of maps on a web page. These maps are originally created by the server using GIS software but are then scanned onto the web page in rastor or vector format. There is no processing of the maps taking place and they are only there for viewing purposes. This type of application is easiest and most popular with companies wishing to graphically display simple spatial data.
Dynamic Map Browser
This type of application has quickly become the DGI of choice for companies offering spatial displays where the client may want to adjust some of the parameters of the map. It is similar to the static map display but rather than simply viewing the maps as they are drawn, the client is able to tailor the map to suit to their own needs by changing the parameters of the map. This "interactive" display is popular with both clients and servers as it improves the efficiency to the display and the quality of the information derived from the map.
Data Preprocessor
This form of application is similar to the Raw Data Download but involves a reformatting of the data to fit the clients individual GIS software. Raw Data is difficult to work with and time consuming to put into a useful form. Preprocessing is extremely attractive to the user because it eliminates this process. Data can be reformatted and then immediately incorporated into the client's software. Although useful this application is difficult to implement into a web based service and therefore is not often used successfully on the web.
Web-based GIS Query and Analysis
This application is the most advanced and useful services on the web. Essentially, it allows the client to use data transmission tools such as HTML language, GIF images or Java techniques to allow the client to interface with the server, performing GIS functions online. Analyses such as buffers, overlays, reclasses and map displays can all be performed over the web. While easiest for the user, this application requires a great deal of programming on behalf of the server.
Net-savvy GIS Software
Net-savvy GIS software is becoming the norm in most commercially available programs. New GIS software usually includes modules which allow the user to link up with the manufacture's web page in order to download data, or even new additions to the software package. This application, contrary to the previous model, involves a heavy workload for the client's computer rather than those of the server. As computing power continues to increase, net-savvy software is becoming standard in any domain, including GIS.
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