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Web & GIS …. Web. GIS • Access without purchasing proprietary software • Data directly from producer • Emerging new market
The challenge of Web. GIS • Creating software systems that work any desktop
Web. GIS architectures • Server-Side • Client-Side • Hybrid
Server-Side • Definition: End users submit requests for data and analysis to a web server. The server processes the requests and returns data or a solution to the remote client. (Thin Client) • Advantages § § § High performance server Eliminate large data sets being sent More control • Disadvantages § § § Bandwidth High performance client machines Every request must be communicated
Server-side Strategies Server Client tasks Map Display browsing Query Analysis Map drawing
Client-Side • Definition: End users can perform some data manipulation and analysis locally on their own machines. (Thick Client) • Advantages § § § Take advantage of powerful client machines Greater control of data to the user Reduced requests sent over the network • Disadvantages § § § Large of amounts of data and applets sent Users may not have a powerful machine Users may not have the training to employ the data and analysis functions properly
Client-side Strategies Server Client tasks Analysis Display Map drawing browsing Query
Real-time GIS • Variations on the client-side strategy can be used • Involves feeding data directly into the system from sensors • Real-time can used to: § § § Monitor vehicle location or traffic conditions Monitor weather and hydrological conditions Track tagged animals in habitat monitoring • Can deliver data across the Internet without the need for dedicated cable, telephone, or radio feeds
Variations on the client-side strategy • Add GIS functionality to Web browsers • The alternatives are to: Download and permanently install a "plug -in" Build capabilities into existing GIS software that runs on the client § §
Variations on the client-side strategy
Combination and Hybrid Strategies • Pure server-side and clientside strategies have distinct limitations: § § Server-side strategies sensitive to Internet bandwidth Client-side strategies are sensitive to the computational power of the client
Hybrid • Definition: Server and Client processes combined to optimize performance and meet special user needs. • Better Matched Solutions for Computer Capabilities • Smart Task Assignments
Combination and Hybrid Strategies
Applications • Mass Market Server. Side • Smaller, GIS Savvy Client-Side • Transactions Maps on Demand Hybrid
Web. GIS trends • Lower access cost • Provide better customer service • Shared data and GIS functionality • “Pay-for-use" mapping and GIS services
GIS Vendors and Products • Four Major GIS Vendors ESRI Auto. Desk Enterprise Information Solutions, Inc. Intergraph Map. Info
ESRI • Arc. View IMS § § § Server-Side strategy Server platform - Windows 95, 98, NT, Unix Client software - Java. Script, Java, HTML, Active X Client platforms - All Client-side data formats - GIF/JPEG images Enterprise Information Solutions, Inc.
ESRI • Map. Objects IMS § § § Hybrid strategy Server platform - Windows 95, 98, NT Client software - Arc. Explorer, Java. Script, Java, HTML, Active X Client platforms - All Client-side data formats - GIF/JPEG images, ESRI shapefiles Enterprise Information Solutions, Inc.
ESRI • Arc. Ims § § § Hybrid strategy Server platform - Windows 98, NT, Unix Client software - Java. Script, Java, HTML, Active X Client platforms - All Client-side data formats - GIF/JPEG images, ESRI shapefiles Enterprise Information Solutions, Inc.
Intergraph • Geo Media Web Map § § § Hybrid strategy Server platform - Windows NT Client software - Plug-in for Active CGM, ASP, VBScript, HTML, Active X Client platforms - Windows 95, 98, NT Client-side data formats - Active CGM Enterprise Information Solutions, Inc.
Map. Info • Map. Xtreme § § § Hybrid strategy Server platform - Windows NT, UNIX, (Map. Xtreme Java) Client software - ASP, VB Script, Java. Script, HTML, Active X Client platforms - All Client-side data formats - As implemented by developer Enterprise Information Solutions, Inc.
Auto. Desk • Map. Guide § § § Hybrid strategy Server platform Client software - Java. Script, HTML Client platforms - All Client-side data formats - GIF/JPEG images Enterprise Information Solutions, Inc.
Web and GIS Demonstration • • • Environmental Navigator Maryland SHA Chart II Real Time Crime Reporting Real Estate Property Viewer Terra. Server
Environmental Navigator • http: //sirb. awm. dnrec. state. de. us/en web/ • Goal § Provide information on contaminant sites available in GIS online • Features § § § Address locator Contaminant site GIS Viewer Criteria query
Maryland SHA - Chart II • http: //www. sha. state. md. us • Goal § Provide traffic monitor information for the State of Maryland • Features § § § From Legacy to Hot Java Web, database, and GIS integration Ad hoc reporting system
Real Time Crime Reporting • http: //www. citymaps. sacto. org • Goal § Provide Real Time Crime Reporting Information for DE • Features § § § Enterprise Web Client/Server Active. X Map Viewer GPS/Wireless Technologies
Real Estate Property Viewer • http: //www. webgis. net • Goal § Provide real estate property information on the Web • Features § § Gigabytes of data records Simple user interface
Terra. Server • http: //www. terraserver. microsoft. com • Goal § Provide Imagery for property assessment, engineering, traffic planning, personal mapping, etc. • Features § § § 1 m to 1 km digital orthoquad imagery Free imagery downloads Site finder and lat/long information